Tellabs 263DC User manual

7te11abs
technical manual
76-81263DC
rev A
practice section 81263DC-1
/81263DC-2/81263DC-3
©Tellabs, Inc., 1May 1984
all rights reserved, printed in USA
263DC Data Station Termination Systems
-
figure 1. 2630C-1 OST Sysfem
page 1
page 2
page 5
page
10
page 12
page 11
page 13
contents
section 1general description
section 2application
section 3installation
section 4 circuit description
section 5
block diagram
section 6specifications
section 7testing and troubleshooting
1. general description
1.01 The Tellabs 263DC-1 (figure
1), 263DC-2,
and 263DC-3 Data Station Termination (DS1)
Systems interface
either a2wire or a4wire data
set
with a4wire transmission facility. All three
systems
are compact, self-contained units that
provide data interface and
power rectification/
regulation circuitry in an attractive enclosure that
can be wall mounted
or placed on adesktop.
Power
for these systems can be provided from
battery feed
or sealing current derived from the
units' simplex leads, or from an external source of
either nominal 26Vac or -22 to -56Vdc. All three
systems feature prescription gain and loss in
the
receive channel, prescription loss in the transmit the 263DC-2 and 263DC-3, this is in addition to
channel, and manual or two-tone loopback In any provided by the receive equalizer) for long
addition, both
the 263DC-2 and 263DC-3 provide sections of nonloaded cable. The facility-side trans-
prescription active equalization in
the receive formers can also be optioned to derive normal
channel. All
three units also include a20mA simplex leads, to provide an internal source of
sealing current source
to provide sealing current sealing current to the facility, or to provide areturn
for
the 4wire facility. path for sealing current applied at the far end of
Note: Throughout the rest of this practice, the term the facility. (The 263DC must be powered from an
2630C refers to all three OST systems unless external source when the sealing-current source
otherwise indicated. option is selected.)
1.02
In the event that this practice section is re- 1.05 On the station side, the 263DC can be
issued,
the reason for reissue will be stated in this optioned to interface either a2wire or a4wire
paragraph. modem. In
either mode, the station-side port(s) pro-
1.03 The
263DC provides from -24 to +24dB of vides capacitively-coupled, balanced, 600-ohm
gain in
the receive channel and from 0 to 24dB of terminating impedance.
loss in
the transmit channel. Transmission levels in 1.06 The 263DC provides loopback of the facility
both channels are prescription-set in 0.1dB incre- for testing and troubleshooting. The loopback func-
ments via DIP switches. The maximum input and tion can be activated either remotely by transmis-
output level of each channel is +5dBm. While the sion of a2713Hz tone or locally via alocal loop-
263DC-1 provides no amplitude equalization,
the back lead. When activated remotely, the 263DC
263DC-2 and 263DC-3 both contain active pre- can be optioned
to restore normal operation upon
scription equalizers in
their receive paths. The receipt of asecond loopback tone or automatically
263DC-2's equalizer is slope-type, providing up
to at the end of a20-minute timeout period (receipt of
7.5dB of gain at
2804Hz (re 1004Hz) in switch- asecond tone before the expiration of this timeout
selectable 0.5dB increments. The 263DC-3's equal- period will also restore normal operation). The
izer is aslope/bump-type equivalent to the Western
263DC system provides equal-level loopback with
Electric modei 309B. switch-selectable gain of 8
or 16dB in the loop-
1.04 Transformers· at both facility-side ports back path.
(receive
output and transmit input) can be switch 1.07 Other standard features of the 263DC
optioned for balanced 1200-, 600-, or 150-ohm System include two 310-type test jacks and five
terminating impedance. The 150-ohm option pro- status-Indicating LEDs. The
test jacks are opening-
vides approximately
2dB of slope equalization (for type and face the DST system at the receive output
page 1

practice section 81263DC-1/81263DC-2/81263DC-3
and transmit input ports. Four of the LEDs are
visible with the unit's cover in place. Ayellow power
on LED lights when power is applied to the unit. A
red loopback LED lights when
the loopback cir-
cuitry is activated. Two other yellow LEOs are
labeled data in and data out; these LEOs light
when data is present in
the receive and transmit
channels, respectively. Afourth yellow LED located
on
the unit's printed circuit board lights when the
internal sealing current source is active and seal-
ing current is flowing.
One optional feature is avail-
able on
the 263DC: apair of gas-tube lightning
protectors for
the facility-side ports (Tellabs part
number 2630 L2).
1.08 The
263DC can be powered remotely
(facility-powered) by sealing current
or battery feed
applied at
the far end of the facility, or can be
powered locally by an external source
of either
nominal 26Vac or -22 to -56Vdc. When facility-
powered,
the 263DC derives its operating voltage
from
the facility via its simplex leads. The 263DC
requires nominal 20mA sealing current or 56Vdc
maximum battery feed
for facility powered opera-
tion. The 263DC's internal sealing current source
cannot be used when the system
is facility-powered.
When powered from an external source,
the
263DC requires 18 to 28Vac or -22 to -56Vdc
input. The nominal 26Vac can be supplied from a
commercial 120Vac, 60Hz outlet through use of a
Tellabs
8015 Transformer, which can be ordered at
the same time as the 263DC. The 263DC con-
sumes amaximum of
30mA of current under
normal operating conditions.
1.09 The 263DC is aself-contained DST system
housed in aplastic enclosure with aremovable
cover. Designed primarily for wall mounting,
the
263DC is also equipped with rubber feet for desk-
top placement. Ahole in the bottom of the cover
(when wall mounted) allows access
to the unit for
external connections. Connections
to the facility
and
power source are made at a17-position screw-
terminal strip. Connections
to the data station are
made
to the terminal strip or to amodular phone
jack (similar to USOC RJ11C).
1.10 The 263DC can be equipped with
two
optional gas-tube lightning protectors for the
facility-side ports (Tellabs part number 2630 L2).
When
the gas tubes are used, the PROT GND pin
on
TB1 must be connected to earth ground for
proper protection from lightning strikes.
2.
application
2.01 The 263DC DST System is used in applica-
tions
where adata station communicates with
other data stations or acentral processor unit
(CPU)
over voice-grade telephone facilities. The
unit provides
the necessary level coordination and
impedance matching
to interface the modem
portion of
either a4wire or 2wire data set with a
4wire facility. If
the data station is provided by the
customer,
the 263DC acts as an interconnect
device, providing end-termination of the telco
facility. Loopback circuitry on the 263DC allows
either local (ground) activation
or remote (two-tone)
activation of facility loopback, with switch-selectable
loopback-path gain of 8
or 16dB. The 263DC-2 and
263DC-3 versions of
the system provide receive-
channel equalization. All
three versions can supply
sealing current
to the facility.
2.02 Level coordination between
the station and
the facility is provided independently in each
channel of
the 263DC. The receive channel pro-
vides up
to 24dB of prescription gain or loss in
0.1dB increments, and
the transmit channel pro-
vides up
to 24dB of prescription loss, also in 0.1 dB
increments. The output levels
of the two channels
are controlled by
the transmit level and receive
level DIP switches (S13 and S19, respectively).
Adjacent
to each DIP switch position is the value,
in dB, of that switch position. These values are
cumulative;
the total amount of gain or loss intro-
duced into achannel is the sum of that channel's
DIP-switch positions set
to in. The maximum input
and output level of both channels is +5dBm. These
level ranges allow
the DST system to easily accom-
modate
the -3 receive TLP (transmission level
point) and
+13 transmit TLP (assuming a -13dBm
OTLP) required by most modems.
2.03 Adata in and adata
out LED on the cover
of
the system light when data is present in the
receive and transmit channels, respectively. The
level
detectors that drive the LEOs respond to data
levels
greater than -25dBm.
2.04 Both the 263DC-2 and 263DC-3 provide
active prescription post-equalization of
the facility
in
their receive channels. The 263DC-2 uses a
slope-type amplitude equalizer
to provide up to
7.5dB of equalized gain at 2804Hz (re 1004Hz) in
discrete 0.5dB increments. The frequency response
of
the 263DC-2's receive equalizer is shown graph-
ically in figure 2and in tabular form in
table 1. The
263DC-3's equalizer is functionally equivalent
to
the Western Electric model 309B Prescription
Equalizer.
In addition to providing slope-type
amplitude equalization,
the 263DC-3 provides
bump-type equalization with variable height and
bandwidth settings. Figures 3and 4
show the
typical response curves for the 263DC-3's equalizer
in the slope mode; figure 3shows the curves for
loaded cable and figure 4shows the curves for non-
loaded cable. Table 2gives
the 1004Hz reference
levels for figures 3and 4
for various settings of the
slope switch. Figures 5and 6 show the typical
response curves
for the 263DC-3's equalizer in the
bump mode; figure 5shows the curves represent-
ing various height settings versus awide bandwidth
setting and figure 6shows
the curves represent-
ing various height settings versus anarrow band-
width setting. Table 3gives
the 1004Hz reference
levels for figures 5and
6. The equalization functions
of both
the 263DC-2 and 263DC-3 are controlled by
DIP switches.
page 2

practice section 81263DC-1/81263DC-2/81263DC-3
7 :>dH MAXIMUM
4KHZ
4KHZ 3KHZ 2KHZ
1KHZ
-2
table 2. Equalized gam (m dB) at 1004Hz
lor 263DC-3 equalizer in slope mode
-2 FREQUENCV
fjgure 6. Typical response curves for 263DC-3
receive-channel
equaiizer in bump mode, BW switch =3
HTSETTINGS
10
,.
6
8
..
C
z•
;;:
C>
2
00
10
HTSElTlNGS
8
,.
12
6
10
..
8
C
z•
"6
C>
2•
2
00
figure 5. Typical response curves for 263DC-3
receive-channel
equalizer in bump mode, BW switch =14
slope
loaded/nonloaded
switch
switch setting
setting
NL
L
a
0.0 0.0
(slope
disabled)
10.4 1.4
20.9 2.6
31.4 3.7
41.8 4.7
52.3 5.5
62.8 6.3
73.4 7.2
83.7
7.8
94.2
8.4
10
4.6 9.0
11 5.0 9.5
12 5.4
10.0
13
5.8 10.5
14 6.2
11.0
15 6.6 11.4
o ~d8 MINIMUM
0',
;0
,;
00
"
30 O~,HJ
2S INCHlMlNTS
"
2804H, 3kHz
FRFOUFNCY
FREQUENCY
table 1. TYPIcal receIve-channel slope
equalization for 263DC-2
JOOlil
figure 2. Typical response curves for 263DC-2
receive-channel
equalizer
'004 HI
o
C>
-2 Z
~2
'::,.
-3 ~6
~15
figure 3. Typical response curves for 263DC-3
receive-channel
equalizer in slope mode, loaded cable
figure 4. Typical response curves
for 263DC-3
receive-channel equalizer in stope mode, nonloaded cable
..
C
Z-1
~
., ~ 1--+''-------1
receive
equalizer equalized gain (in dB)
introduced at va,ious frequencies
,witch
setting (dB 300Hz 400Hz 500Hz
800Hz 1004Hz 1500Hz 1800Hz 2500Hz 2804Hz
0 00 00 00
00 0.0 00 0.0 00 0.0
0;
- 0.23 -0,19 - 0.15
-0,06
00
+0.1~ '0.24 +043 +0.50
, .0 -0,~2
042
-0,33 0.13
00
+0.32 -.-0,52 +0.93 +1,07
, .5 0.75 -0,60 0,49 -0,18
00
+0.46 -+0.74 +1.33 +1.54
"
-100 -0.80 -0.64
-0,24
0.0 +0.61 +0,98 -+1.76
-.-2,04
'.5
-1,22
0.98
-0.78 0.29 0.0 +0,75 +1,20 12.15 +2,49
3.0
-1.50
-1.20 -0.95
-0,36
00
+0,90
'1.45 +2,60 +3.01
35
1.71
-1,37 -1.09
-0,41
00
+1.03 -.-1.65 +2,97 +3,45
'.0
2.02
-1.63 -1.29
-0,49
0.0 -+1.22 +1,95 +3.54 +4.12
"
-2,25
1.79
-142
- 0.53
0.0 +1.33 +2.14
13.90 +4.56
50
-249
-1,98
-1.57 -0,59
00
-'-1,47
t2.36 +4,32 -+5.08
5.5
-268 -2.14 - 1,69
-0.63
0.0
,1.58 +2,53
'4.67
+5,51
6.0
-2.89
-2.30 -181
-0.68
0.0 +1.69 -+2.72 +5.05 +5,99
65
3.07
-2.44 1.93
-0.72
00
+1.79 1287 +5.38
1641
"
-3.29
2.61
-2.05 -0.76
00
1189 +3.05 +5.76 +6.90
75
-3.45
-2.74
-2,15 -0,78
0.0 +1.98
+319
+6.06 -.-730
"
•12
10
8
6
•SLOPE
2
SETTINGS
2
•
0
Z0
"
~
-2
page 3

practice section 81263DC-1/81263DC-2/81263DC-3
HT
switch
BW switch setting**
setting*
6 7 8 9 10 11
12 13 14 15
2 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.1 0.1
0.2
3 0.0 0.0 0.0 0.0
0.0 0.0 0.1 0.1 0.1
0.3
4 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.1
0.2 0.4
5 0.0 0.0 0.0 0.1
0.1 0.1 0.1 0.2 0.3 0.5
6 0.0 0.0 0.1 0.1 0.1 0.1
0.2 0.2 0.4 0.7
7 0.0 0.1 0.1 0.1 0.1
0.2 0.2 0.3 0.5 0.9
8
0.0 0.1 0.1 0.1
0.2 0.2
0.3 0.4 0.7 1.2
9 0.0 0.1 0.1
0.2 0.2 0.3 0.4 0.5 0.8
1.5
10
0.0 0.1 0.2 0.2 0.2 0.3 0.4 0.6
1.0 1.7
11 0.1 0.1
0.2 0.2 0.3 0.4 0.5 0.7
1.2 2.0
12 0.1 0.1 0.2
03 0.3 0.4 0.6 0.9 1.4 2.4
13 0.1 0.2 0.3 0.3 0.4 0.6 0.8
1.1
1.7 2.8
14 0.1 0.2 0.3 0.4 0.5
0.7 0.9 1.3 2.0 3.3
15 0.2 0.3
0.4 0.5 0.7 0.9 1.2 1.7 2.5
3.9
*HT switch position adisables bump function. HT switch position 1introduces 0.1dB of gain or less at 1 kHz.
**BW switch positions athrough 5introduce 0.1dB of gain or less at 1kHz for all HT seltings.
table 3. Equalized gain at 1004Hz for 263DC-3 equalizer in bump mode
2.05 The transformers at the facility-side ports of permitting the maintenance responsibility involved
the 263DC can be switch-optioned for 1200-ohm in a particular case of trouble to be determined.
terminating impedance to interface loaded cable, 2.09 The 263DC's loopback circuitry can be
for 600 ohms to interface nonloaded cable or car- activated either remotely by transmission of nominal
rier,
or for 150 ohms to provide approximately 2dB 2713Hz loopback tone from the far end of the facil-
of equalization (in addition to any provided by the ity or locally by grounding the system's loop back
263DC-2's or 263DC-3's receive equalizer) for long lead. Loopback will not occur accidentally because
sections of nonloaded cable through the deliberate of power failure. When loop back is activated, the
impedance mismatch. Both facility-side transformers loop back (LB) relay operates, disconnecting the
on the 263DC are center-tapped to derive balanced station from the data circuit and looping the receive
simplex leads. path back to the transmit path. Additional contacts
2.06 The station-side ports of the 263DC can be of the LB relay electrically disable the data station
optioned to interlace either 4wire or 2wire data via the 263DC's TEK5 and TEK6 leads. The foop-
sets. In the 2wire mode, an electronic hybrid pro- back LED on the system's cover lights to indicate
vides the necessary 4wire to 2wire conversion. that loopback is activated.
Both the 2wire and 4wire ports provide fixed, 2.10 Remote loopback is accomplished by plac-
capacitively-coupled 600-ohm terminating imped- ing a 2713Hz tone on the receive pair of the
ances toward the station. 263DC for at least 1.6 seconds and then removing
2.07 An option switch on the 263DC selects the tone. The 263DC initiates loopback only upon
either internal sealing current, external sealing cur- the removal of the tone. This prevents accidental
rent,
or normal simplex leads. In the SOURCE looping of other than the intended loopback point
position, the center-tapped leads of the facility-side on amultipoint circuil. The threshold of the loop-
transformers are
connected to anominal 20mA back-tone-detection circuit is -30dBm as meas-
integral sealing current source. In the SINK posi- ured at the receive input porI. The loopback tone
tion, these leads are connected together to pro- detector's center frequency is 2713Hz ±0.20/0 with
vide ade path for sealing current applied at the far amaximum bandwidth of 75Hz. Asignal-to-guard
end
of the 4wire facility. The SX position provides ratio of 6dB prevents either raw data signals or
normal simplex-lead derivation. An LED on the harmonics of those signals from initiating loopback,
263DC's printed circuit board lights when the thus allowing the 263DC to operate in circuits
internal sealing-current source is active and cur- where similar units might be prone to false
rent is flowing. loopback. Aswitch option allows remote
loopback
2.08 The 263DC DST System can serve as a to be deactivated by asecond 2713Hz loopback
testing and troubleshooting device through its tone of O.7-second duration or longer (removal of
ability to isolate the facility from the station via the tone is not necessary to deactivate loopback),
loopback. The loopback feature allows
the voice- or automatically after a 20-minute timeout period.
frequency characteristics of the facility to be tested 2.11 Local loopback is initiated by placing a
from aremote location (e.g., the serving CO). Loop- ground on the local loop back lead (LOC LB
back also allows the source of trouble to be local- terminal of TBI). Loopback is maintained until the
ized to either the facility or the data station, thus ground is removed.
page 4

practice section 81263DC-l/81263DC-2/81263DC-3
clears the unit's chassis. The cover is replaced by
reversing this procedure.
mounting
3.03 The 263DC is wall mounted via three screws
(not supplied) inserted
through holes in the base
plate
of the unit. A template for positioning the
screws is proVided at the end of this practice. Four
rubber feet are supplied for desktop placement.
installer connections
3.04 Before making any connections to the
263DC, ensure that power is not applied to the
unit. Power should be connected to the unit only
after all other installer connections are made and
after the unit is properly optioned.
3.05 Make all telco connections (facility-side
ports and simplex leads) to the 263DC at 17-position
terminal block TBI. The modem connections (station-
side
ports and data disable leads), however, can be
made
at TB I or via the modular phone jack (similar
to USOC RJllC), J3, supplied with the unit. Access
to both
TB Iand J3 is through the bottom of the
unit. Connections to the 263DC are listed in table 4.
Note: When the 263DC is equipped with the
optional gas-tube lightning protectors, the PROT
GND terminal on TB1
should be connected to a
separate earth ground to provide maximum light-
ning protection.
connect:
toTBl pin:
facility:
XMTOUTTIP
............ ........... .. ............. IT
XMT OUT RING. ........ ,- ... TR
RCV IN TIP .... - ..........................
..... .... RT
RCVINRING .............................. ........ RR
simplex leads:
SX TRANSM IT ..........
.. .. .................... ..SXT
SX RECEiVE ......
. ................. ~R
data station:
XMT IN TIP/2WIRE TIP
............... DIT/2WIRE TIP
(or J3 pin 4)
XMT IN RING/2WIRE RING ........ DTR/2WIRE RING
(or J3 pin 3)
RCV OUT TiP ........................ DRT (or J3 pin 2)
RCVOUTRING
..................... ORR (or J3 pin 5)
DATA SET DISABLE ................ TEK5 (or J3 pin 1)
DATA SET DISABLE ................ TEK6 (or J3 pin 6)
power:
AC OR DC INPUT ......
....... . .................... AC
INPUT GROUND ..........
.................. CKTGND
EARTH GROUND .............
.... ....... PROTGND
(only when optional
gas tube
lightning protectors are used)
loopback:
local loopback ......
. ...................... LOC LB
3. installation
inspection
3.01 The 263DC Data Station Termination System
should be visually inspected upon arrival to find
any damage incurred during shipment. If damage is
noted, aclaim should immediately be filed with the
carrier. If stored, the unit should be visually inspected table 4. External connections to 263DC
again prior to installation. 3.06 To power the 263DC from alocal external
cover removal source of either nominal 26Vac or -22 to -56Vdc,
3.02 To instali the 263DC System, its protective make power connections to the AC terminals of
plastic cover must be removed. The cover is held in TB I(polarity need not be considered in either
place by a single captive screw in the bottom of the case). If the Tellabs 8015 Transformer is used to
unit. To remove the cover, loosen the screw and supply the required ac voltage, connect terminals I
swing the bottom of the cover up and out until it and 3 of the 8015 to the AC terminals of TBI, and
page 5
2.12 Equal-level
loopback is provided by an
amplifier in the 263DC's loopback path. This ampli-
fier can be switch-optioned to insert either 8 or
16dB of gain between the receive channel and the
transmit channel when the loop back circuitry is
activated. Thus, in adata circuit with
either an 8 or
16dB difference between the receive and transmit
TLPs, a
test signal transmitted from the far end of
the facility at the normal data transmission level will
be returned
at the normal receive level. In data cir-
cuits with aTLP differential other than 8 or 16dB,
the gain inserted into the loopback path must be
considered when making transmission level tests.
(Please
note that this problem can be avoided by
setting the amplifier for 8dB and inserting an addi-
tional
8dB of attenuation into the transmit channel
via
the xmt level switches while testing is in
progress.)
2.1 3The 263DC can be powered locally from an
external source of either nominal 26Vac or -22 to
-56Vdc, or it can be powered remotely from de
applied at the far end of the facility and derived
from the facility by the 263DC's simplex leads. The
power source is selected by aswitch option that con-
nects the input of the 263DC's power rectification/
regulation circuitry to the AC terminals of TB I or to
the simplex leads. When powered externally, the
263DC requires 18 to 26Vac input at 7.5VA or -22
to -56Vdc input at 15mA minimum. The required ac
input can be supplied from acommercial 120Vac,
60Hz grounded outlet by using aTellabs 8015
Transformer (ordered separately). When powered
remotely, Le., facility-powered, the 263DC requires
aminimum
of 20mA dc, which can be supplied by a
regulated sealing-current source
or by direct bat-
tery feed to the 4wire loop. To ensure proper opera-
tion of the 263DC when it is facility-powered, the
ioop length between the 263DC and the power
source should not exceed 1000 ohms for sealing
current or 2000 ohms for battery feed. Also, when
powered by battery feed, the voltage across the
263DC's simplex leads must not exceed 56Vdc. Both
facility-powering schemes are shown in figure 7.
Note: The 263DC's integral sealing current source
can be used only when the 263DC is powered
externally.

practice section 81263DC-l/81263DC-2/81263DC-3
4WIRE
FACILITY
FAR-END DST 263DC
(( RT [>
~
RCV
~
~
RCV
II
IN {
OU,
JJ
RR
FAC
NOMINAL
8AC
~
_-v
20mA POWER
EXT PWR *S17
RECTIFICATION/
MODEM
de SEALING
CURRENT
AC C
REGULATION
"l
SOURCE
PWR
-
II
TT
-
~
XMT
{
<J
~
XMT
II OUT
{
IN
JJ
TR
263DC/DC-2 line-powered by sealing current
4WIRE
FACILITY
FAR-END DST 263DC
"RT
[>
~
"RCV {
~
RCV
."IN {
OUT
"
RR
FAC
MAXIMUM
...L
~
_-V
±56Vdc AC POWER
BATTERY
-EXTPWR*S17
RECTIFICATION/
MODEM
FEED AC C
REGULATION
""l
-BATT
PWR
-
II
-
TT
<J
~
XMT
oj
~
XMT
II
OUT
~
IN
"TR
263DC/DC-2 tine-powered by battery feed
*517 mustbe settothe FAC PWR position for facility powering
of the 263DC. 517 must be set to the EXT PWR position to
supply sealing current to the facility.
figure 7. 263DC remote powering schemes
then plug the 8015 into a grounded 120Vac, 60Hz
outlet. When
the 263DC is facility-powered, con-
nect aregulated source of 20mA sealing current or
nominal 48Vdc battery across the facility at the far
end as shown in figure 7_Option switch S17 must
be set
to the proper position for either external
power or facility power; see paragraph 3.12. As
stated above, power
connections to the 263DC
should be made only
after all other connections
are made and
after the unit is properly optioned.
optioning
3.07 Optioning the 263DC consists of selecting
the facility-side impedance, the 2wire or 4wire data
set interface,
the loopback path gain, the tone-
loopback release option, the power option, and
selecting external
or internal sealing current or
normal simplex-lead derivation. The locations of the
option switches are shown in figure 8. Table 5con-
tains a
brief explanation of the functions and set-
tings of each option switch plus aconvenient
optioning checklist. The checklist can be filled
out
(by checking the appropriate box for each switch)
either prior to installation to allow for prescription
optioning of the unit or as the unit is being optioned
to provide arecord for future reference. Detailed
instructions
for optioning the 263DC are provided
in
the following paragraphs.
3.08 Switch
SII selects balanced 1200-, 600-,
or 150-ohm impedance at
the facility-side ports
(receive input and transmit output). Set S
11 to the
1200, 600, or 150 position as required. Generally,
the 1200-ohm option is used for loaded cable, the
600-ohm option is used for nonloaded cable or car-
rier, and
the 150-ohm option is used to provide a
small amount of slope equalization for long sections
of nonloaded cable through a
deliberate imped-
ance mismatch.
3.09 Switch S14 selects
the desired data-station
interface,
either 2wire or 4wire. Set S14 to the 2W
position to interface a2wire modem or to the 4W
position to interface a4wire modem.
3.10 Position 1of switch S15
selects the amount
of gain inserted between the receive channel and
page 6

practice section 81263DC-1/81263DC-2/81263DC-3
figure 8. 263DC option sWItch locatIOns
table 5. 263DC option summary and checklist
the transmit channel when the unit is in loopback
(see paragraph 2.12).
To insert 8dB 01 gain into the
loopback path, set S15-1 to the 8position. To insert
16dB of gain into
the loopback path, set S15-1 to
the 16 position.
check-
function switch selections settings list
facility-side
S11
150 ohms
150
port impedances
(rev out and 600 ohms 600
xmt in)
1200 ohms
1200
data-station S14 2wire 2W
interface
4wire 4W
loop back-path S15-1 adS gain 6
gain
16dB gain 16
tone loopback S15-3 normal (two
OFF
release
tone)
timeout
TO
(20 minutes)
tone loopback
S15-2 enabled n
disable
disabled
OFF
facility or
S17 facility FAC PWR
external power via
power SX leads
external EXT PWR
power
sealing current S18 internal
SOURCE
sealing-
current source
de return
SINK
path for
far-end source
normal SX
simplex
leads
3.11 Position 3of S 15 selects the tone-Ioopback
release option. For normal two-tone operation
(Ioopback released by second loopback
tone only),
set S
15-3 to the OFF position. For timeout operation
(Ioopback released automatically
after 20 minutes
unless asecond tone is received prior
to that time),
set S15-3
to the TO (on) position. Position 201 S15
disables the tone loopback circuit. For normal opera-
tion (tone loopback enabled) set S15-2
to the IT
(on) position. 11 tone loopback is not desired, setS15-2
to the OFF position. In either case, loopback can
still be activated locally via
the local ioopback lead.
3.12 Switch S17 selects
either facility power or
external power. To power the 263DC from sealing
current
or battery feed via the simplex leads, set
S17
to the FAC PWR position. To power the 263DC
from an external source of nominal 26Vac or of
-22 to -56Vdc, set S17 to the EXT PWR position.
Note: The 263DC must be powered from an
external source when the 20mA sealing current
source is used.
3.13 Switch
SIB selects the desired sealing cur-
rent option.
To supply 20mA of sealing current to
the facility from the 263DC's internal current
source, set S18
to the SOURCE position. To pro-
vide areturn path for sealing current supplied from
the far end of the facility, set S18 to the SINK posi-
tion. If normal simplex lead derivation is desired,
set
SIB to the SX position.
Note: The 263DC's integral sealing current source
can
only be used when the 263DC is powered from
an external source.
alignment
3.14 Alignment 01 all three versions of the
263DC consists of setting the transmit and receive
transmission levels and, for
the 263DC-2 and
263DC-3 only, setting the receive-channel amplitude
equalization if required. After all
options on the unit
are selected,
two methods of alignment are avail-
able: prescription
or direct measurement (non-
prescription). With
the prescription method, the
unit's alignment switches are set according to the
specifications on the circuit layout record or on a
computer printout. In cases where the information
supplied by
the CLR or printout is inadequate or
unavailable, it is necessary to perform the non-
prescription alignment procedure. The procedure
for prescription alignment of
the 263DC's transmit
and receive transmission level is given in para-
graph 3.15;
the non-prescription alignment pro-
cedure is given in paragraphs 3.19 and 3.20 (long
form) and in figure 9(condensed form). The pre-
scription and non-prescription alignment procedures
for
the receive-channel equalizer on the 263DC-2
are given in paragraphs 3.16 and 3.21, respectively.
The prescription alignment procedure
for the
263DC-3's receive-channel equalizer is given in
paragraph 3.17; information on non-prescription
alignment
01 the 263DC-3's equalizer is provided in
paragraph 3.22.
Note: To place the 263DC into loopback for test-
ing,
either transmit a2713Hz tone burst at alevel of
page 7
o
"~'" . OFF TT
OFF TO
o
LOOP
BO~
DATA
o
DATA
o
POWE~
o

practice section 81263DC-1 /81263DC-2/81263DC-3
515
16~8
OFF TT
OFF TO
1 Refer to the CLR and determine the
following: facility port impedances, re-
Quired
receive output level, and transmit
input level. Ensure that 811 (facility port
impedance) is set correctly. Then pro-
ceed to step 2and perform the alignment
procedures in numeric order. The para·
graphs referenced in the procedure
headings provide a more detailed ex-
planation
of that specific procedure.
o
LOOP
BACK
o
DATA
IN
o
DATA
OUT
o
POWER
ON
o
GN~L5
.1 ~
.2 !!.
M .4 ~
@+~'I ~
12 B!
C6»~·.I-"
_IN
o
00
FAC
50:~~~ ~ rjlt
150600 1200 ~EXT
~ ... 518 PWR
I~- I ~ V1~t ::R
YQ RR
10 CKT
V2~ ~ ~~D
Y \y SXT
®® ~~r.
4W +- +- <9 ORR
~OO (Qj (Q] ~ ~~;
2W RCV OUT I~~~ 0TEK5
o TEK6
~
0AC
oAC
J3_ ~~~7,T
Receive Level (paragraph 3.19)
2 Arrange the receive portion of the
TMS for 600~ohm terminated measure-
ment and connect it to the RCVOUTjack
(XMT IN/2W jack for 2wire operation).
3 Have the far end transmit 1004Hz
test tone at the level specified on the
CLR. Measure the received level.
4Ifthespecified receive level is higher
than themeasured level, set513-1 tothe
GNposition. If the specified level is lower
than the measured level, set 813·1 lathe
LS position. Then set the rev level (813-2
through 813-9) switches in the proper
combination to achieve the specified
output level.
Transmit Level (paragraph 3.20)
5 Arrange the transmit portion of the
TMS (terminated at 600 ohms) for
1004Hz tone output at the CLR- speci-
fied level, and connect it to the XMT IN/
2Wjack.
6Have the far end measure and re-
port the received level. Then set the xmt
level (819) switches in the proper com·
bination to achieve the specified level at
the far end.
Receive Equalization (263DC·2 only;
see paragraphs3.17 and 3.22 for the
263DC-3) (paragraph 3.21)
7 Connect the receive portion of a
properlyterminatedTMS tothe RCVOUT
jack (X MT I N/2 WIRE iack for2wireopera-
tion). Have the far end send 1004Hz and
2804Hz test tones at the CLR-specified
level. Measure and record these levels.
8 Subtract the 2804Hz level from the
1004Hz level.
9 Set to in the proper combination of
equalization switches on the equalizer
subassembly that most closely approx-
imates the amount arrived at in step 8.
figure 9. Condensed non-prescription alignment procedures
30dBm or higher for at least 1.6-seconds and then switches to achieve the required levels. The specific
remove the tone (remote loopback), or apply aamount of loss or gain (in dB) introduced by each
ground to the local loopback lead. To restore normal DIP-switch position is indicated on the switch body
operation, either transmit a second tone burst for at adjacent to the switch position. These switch posi-
least 0.7 second or remove the ground from the tions are cumulative; the total amount of flat loss or
local loopback lead. gain introduced into achannel is the sum of that
prescription transmit and receive level channel's DIP-switch positions set to in. Switch set-
adjustment (263DC-1, -2, -3) tings and achecklist for prescription level adjust-
3.15
To adjust the transmit and receive levels on ment are provided in table 6.
the 263DC via the prescription method, proceed as 263DC-2 prescription receive equalizer
tollows: From the CLR, determine whether gain or alignment
loss is required in the receive channel and set the 3.16 To adjust the receive equalization on the
GN/L5 switch (513-1) to the appropriate position 263DC-2 via the prescription method, proceed as
(L5 or GN). Next, determine (from the CLR) the follows: From the CLR, determine the amount of
amount of loss
or gain required in the receive chan- equalized gain required at 2804Hz (re 1004Hz).
nel and
the amount of loss required in the transmit Equalization is introduced into the receive channel
channel. Then set to in
the proper combination of via the equalizer DIP switch on the equalizer sub-
transmit levei (519) and receive level (513) DIP assembly. The specific
amount of equalized gain at
page 8

practice section 81263DC-1 /81263DC-2/81263DC-3
table 8. 263DC-2 rounded equalizer SWitch settings
263DC-3's receive equalizer consists of entering
the pertinent data into acomputer-controlled cir-
cuit design system that provides a printout specify-
ing
the required equalizer switch settings. The BW
and HT switches, or the slope and loaded/nonloaded
switches are then set as directed. The 263DC-3's
receive equalizer can also be aligned by determin-
ing
the facility characteristics from the CLR and
then setting the receive equalizer switches as indi-
cated in Tellabs practice
section 819908B or Bell
System Practice (BSP)
section 332-912-222. These
practices contain extensive listings of various facility
characteristics (including
combinations thereof)
and the equalizer switch settings required to com-
pensate for these. The 263DC-3's equalizer switch
sellings and achecklist for prescription equalizer
alignment are given in table 7.
post-alignment testing
3.18 After the transmission levels and receive
equalization are set, it may be desirable
to confirm
the results via end-to-end tests. Where computer-
controlled
test equipment is used, a subsequent
printout will verify the alignment results. Any devia-
tion from
the required levels can then be adjusted
via the appropriate switches. If computer-controlled
test equipment is not available, the alignment
results can be confirmed by performing the mea-
surements in the condensed test procedures in
figure 9.
non-prescription receive· level adjustment
(263DC-l, -2, -3)
3.19
To adjust the receive level of the 263DC
when prescription level settings are not given in
the CLR or when the given settings do not produce
adequate results, proceed as follows:
A. Ensure that no receive level DIP-switch posi-
tions are set to in. Also ensure that the facility-
side port impedance switch (SI1)
is set correctly.
B. Arrange the receive portion of atransmission
measuring set (TMS)
for 600-ohm terminated
measurement and connect it to the ReV OUT
jack (XMT IN/2Wfor 2wire operation). Have the
far end send 1004Hz test tone at the specified
level.
2804Hz (re 1004Hz) introduced via each DIP-switch
position
is indicated on the printed circuit board
next
to the switch position. These switch positions
are cumulative; the total amount of equalized gain
(0 to 7.5dB) introduced is the sum of those DIP-
switch positions that are set to in. The 263DC-2's
receive equalizer switch
settings for prescription
equalizer alignment and a checklist are given in
table 7. Because the required amount of equaliza-
tion given in the CLR may be specified to the
nearest 0.1 dB while the equalization switch is ar-
ranged in 0.5dB increments, table 8gives the
rounded switch sellings fo the equalizer's full range.
function switch
settings(in dB) checklist
rev loss
S13-1
LS
or gain GN
rev level S13-2
.1
through
.2
S13-9
.4
.8
1.5
3
6
12
xmt level S19-1
.1
through
.2
S19-8
.4
.8
1.5
3
6
12
table 6. 263 DC level alignment switches and checklist
DSTunit function
switch
settings
checklist
263DC-2 receive slope
S1 0.5
equalization
1
gain at 2
2804Hz 4
(re 1004Hz)
263DC-3 loaded/non-
S1-1 NL
loaded cable L
slope
S1-2
1
through 2
S1-5
4
8
height
S2-1
1
through 2
S2-4
4
8
bandwidth
S2-5 1
through 2
S2-8
4
8
table 7. 263DC-2 and 263DC-3 receive equalization
switches and checklist
263DC·3 prescription receive equalizer
alignment
3.17 Because the 263DC-3's receive equalizer
switch
settings are totally dependent upon the
characteristics (e.g., cable gauge and length,
loaded
or nonloaded, etc.) of the facility to which
the unit is connected, it is recommended that the
equalizer be aligned via the prescription method
only. In most cases, prescription alignment of the
page 9
1000Hz·2804Hz
difference
0.0 to 0.2d8
0.3 to 0.7d8
0.8 to 1.2d8
1.3 to 1.7dB
1.8 to 2.2dB
2.3 to 2.7d8
2.8 to 3.2dB
3.3 to 3.7dB
3.8 to 4.2dB
4.3 to 4.7dB
4.8 to 5.2dB
5.3 to 5.7dB
5.8 to 6.2dB
6.3 to 6.7dB
6.8 to 7.2d8
7.3 to 7.7dB
amount of equalized
gain required
O.OdB
0.5d8
1.0dB
1.5dB
2.0dB
2.5dB
3.0d8
3.5dB
4.0dB
4.5dB
5.0dB
5.5dB
6.0dB
6.5dB
70d8
7.5dB

practice section 81263DC-1/81263DC-2/81263DC-3
C. Now have the far end send 2804Hz test tone at
the level specified on the CLR. Measure and
record
the received 2804Hz level. Subtract the
2804Hz level from the 1004Hz level recorded
in step
B.
D. Set to in that combination of equalizer DIP
switch positionswhich approximates as closely as
possibie
the measured difference (see table 8).
263DC-3 non-prescription receive equalization
adjustment
3.22 For anon-prescription alignment procedure
for
the 263DC-3's receive equalizer, please refer to
BSP 332-912-221.
4. circuit description
4.01 This circuit description is intended to famil-
iarize you with
the 263DC Data Station Termination
System
for engineering and application purposes
only. Attempts
to troubleshoot the unit internally
are not recommended and may void
your warranty.
Troubleshooting procedures should be limited
to
those prescribed in section 7of this practice. Refer
to the 263DC block diagram, section 5 of this prac-
tice, while reading this circuit description.
4.02 The unit's
power supply consists of afull-
wave bridge rectifier, acapacitor
input filter, and a
series voltage regulator. The full-wave bridge rectifier
allows
the unit to be powered from either ac or de
input voltage. The capacitor input filter provides
isolation from ac signals present on
the line, and,
when ac
power is used, eliminates 60Hz interfer-
ence from
the signal path. The series voltage regu-
lator is used
to derive astable de voltage for the
internal circuitry.
4.03 Transformers at the facility-side ports (receive
input and transmit output) are
tapped to provide
switch-selectable 1200-, 600-,
or 150-ohm termi-
nating impedance. Asilicon voltage-transient sup-
pressor on
the secondary side of each transformer
limits transient potentials to asafe level and pro-
vides surge protection. Both transformers are
center-tapped
to derive balanced simplex leads. A
20mA current source provides an internal source of
nominal 20mA sealing current. The 20mA current
source can be switch-optioned
to provide sealing
current
to the facility via the unit's simplex leads, to
provide areturn path for sealing current supplied at
the far end of the facility,
or to derive normal simplex
leads. Aseal
curr LED on the unit lights when the
internal 20mA current source is selected and cur-
rent is flowing.
4.04 The station side of
the 263DC can be op-
tioned
to interface either a2wire or 4wire data
station as selected by switch S14. An
electronic
hybrid circuit provides the necessary 2wire-to-
4wire conversion in
the 2wire mode.
4.05 Levels between
the facility and the data
station are coordinated by
the receive amplifier and
the receive-level-control circuit. DIP switches in the
receive-level-control circuit introduce controlled
feedback into the receive amplifier circuitry to pro-
page 10
C. If the level measuredat the RCVOUT(orXMT IN/
2 W) jack is the sameas that specifiedon the CLR,
proceed
to the transmit level adjustment pro-
cedure (paragraph 3.20). If the measured level is
lower than
the specified level, set the GN/LS
switch(SI3-1) tothe GN position; if the measured
level is higher than
the specified level, set S13-1
to the LS position. Then set to in that combination
of receive level DIP switch positions which equals
the required amount of gain or loss (i.e., the dif-
ference between
the specified level and the
measured level).
Note: The amount of gain or loss introduced by
each position
of the receive level switch is indicated
on the switch body. These switch positions are
cumulative; the total
amount of gain or loss intro-
duced is the sum of those switch positions set to in.
non-prescription transmit-level adjustment
(263DC-1, -2, -3)
3.20
To adjust the transmit level of the 263DC
when prescription level settings are not given in
the CLR or when the given settings do not pro-
duce adequate results, proceed as follows:
A. Ensure that no transmit level DIP-switch posi-
tions
are set to in. Also ensure that the facility-
side port impedance switch
(SII) is set correctly.
B. Arrange the transmit portion of aTMS (properly
terminated at
600 ohms) to output 1004Hz
toneatOdBm
(or other datalevel specified by the
CLR), and connect it to the XMT IN/2W jack.
C. Have personnel at the far end measure and
report
the received ievel; the difference between
the measured level and the specified level is
the amount of loss required in the transmit
channel of
the DST unit. Set to in that combi-
nationoftransmit
level(SI9) DIPswitch positions
which equal the required amount of attenuation.
Note: The amount of loss introduced by each
position
of the transmit level switch is indicated on
the switch body. These switch positions are cumula-
tive; the total
amount of gain or loss introduced is
the sum
of those switch positions set to in.
263DC-2 non-prescription receive equalization
adjustment
3.21 To determine the need for receive-channel
equalization
(I.e., post-equalization at the local end
of
the 4wire facility) and to make the required
adjustments when
the 263DC-2 is used, proceed
as follows:
A. Ensure that none of the four equalizer DIP-
switch positions are set
to in. Also ensure that
the facility-side port impedance switch (SII) is
set correctly.
B. Arrange the receive portion of aTMS for 600-
ohm terminated measurement and connect it
to the RCVOUTjack(XMT IN/2 Wfor 2wire opera-
tion). Have
the far end send 1004Hz test tone at
the level specified on the CLR. Verify the pres-
ence of test tone and record the measured
level.

practice section 81263DC-l /81263DC-2/81263DC-3
envelope delay distortion
less than 100 microseconds, 400 to 3000Hz
peak/average ratio
greaterthan 98
I receive channel I
level range
o to 24dB of gain or loss in switch selectable 0.1dB
increments, with gain or loss selected via switch
option
input impedance
150ohms ±15%, 600 ohms ±10%, or 1200 ohms
±10%, balanced, switchable
total harmonic distortion
1% maximum, 300 to 4000Hz
2630C-2 equalization
up to 7.5dB of active slope equalization at 2804Hz
(re 1004Hz) in switch-selectable0.5dB increments
2630C-3 equalization
slope/bump equalizer for loaded or nonloaded cable
-equivalent to Western Electric 30gB
-30dBm. Aminimum 6dB guard band prevents
remote
loopback activation by other than the in-
tended signal. Local loopback is deactivated by
removing the ground from the
LOC LB lead. Remote
loop
back is deactivated in either of two ways: upon
receipt of asecond 2713Hz tone burst of 0.7
second
or longer, or automatically after a20-minute
timeout period. The method of remote loopback de-
activation is selected via switch option. When
the
timeout method is selected, loopback can still be
deactivated by transmission
of a second 2713Hz
tone before the timeout period expires. An option
switch is also available to disable the remote-Ioop-
back function completely when desired.
4.12 Aloopback amplifier in
the loopback path
can be switch-optioned to provide either 8 or 16dB
of gain between the receive and transmit channels
when the unit is in the loopback mode. In circuits
with
either an 8 or 16dB differential between the
receive and transmit TLPs, this feature allows a test
signal received at the normal data level to be re-
turned
to the remote location at the same level as
in normal operation.
specifications continued on page 13
specifications
noise
10dBrnCO maximum
maximum input level
+5dBm
maximum output level
+5dBm
6.
vide up to 24dB of gain or loss in the receive
channel in O.ldB increments. One of the DIP switch
positions determines whether gain or loss is inserted
by the receive amplifier.
4.06 Both the 263DC-2 and 263DC-3 provide
active post-equalization of the facility via integral
prescription
amplitude equalizers in their receive
channels. The 263DC-2's receive equalizer is
slope-type, providing
up to 7.5dB of equalized gain
at
2804Hz (re 1004Hz) in discrete 0.5dB increments.
The
263DC-3's receive equalizer is functionally
equivalent to the Western Electric model 309B
Prescription Equalizer. In addition to providing
slope-type equalization, the 263DC-3 provides bump-
type equalization with variable height and bandwidth
settings. The equalization
functions of both the
263DC-2 and the 263DC-3 are controlled by DIP
switches on the receive equalizer subassemblies.
4.07 The receive level detector responds to the
presence of data in the receive channel at levels
greater than -25dBm by lighting the data in LED.
The location
of the receive level detector in the
circuit-following the receive amplitier and receive-
level-control circuit and, on the 263DC-2 and
263DC-3, the receive
equalizer-makes it avaluable
troubleshooting aid because it provides a check on
virtually all active circuitry in
the receive channel.
4.08 Level coordination
between the data sta-
tion and the facility is provided by the transmit
amplifier and the transmit-level-control circuit. A
five-step
attenuator in the transmit-level-control cir-
cuit provides up to 24dB of flat loss in 0.1 dB incre-
ments. This loss is inserted into the transmit
channel via an eight-position 01 Pswitch.
4.09 The transmit level detector performs the
same functions for the transmit channel as the
receive level detector does for the receive channel,
responding to the presence of data signals above
-25dBm by lighting the data out LED. The transmit
level
detector is similarly located at apoint in the
circuit where it provides a check of the maximum
amount of active transmit-channel circuitry.
4.10 The loopback control circuitry provides the
detection, timing, and logic functions for loopback
operation of the 263DC. The loopback circuitry can
be activated either locally via ground or remotely
via 2713Hz tone (see paragraph 4.11). When loop-
back is activated by either method, the loopback
(LB) relay operates, opening the transmit and re-
ceive
channels toward the modem and connecting
the receive channel to the transmit channel. The
LB relay also provides data-set-disable leads (TEK5
and TEK6) to disable the associated data set during
loopback. The loopback LED on the unit's cover
iights
when the unit is in loopback. I I
transmit channel
4.11 Loopback is activated locally by applying .
ground to the LOC LB lead. Remote loopback is level range
activated by application of a 2713Hz tone burst 1.6 0 to 24dB of loss in switch-selectable0.1dB
seconds or longer in duration; the 263DC does not increments
go into loopback until the tone is removed. The maximum input level
threshold of the tone-detection circuitry is fixed at +5dB
page 11

maximum output level
+5dB
output impedance
150 ohms ±15%, 600 ohms ±10%, or 1200 ohms
±10%, balanced, switchable
total harmonic distortion
1% maximum, 300 to 4000Hz
frequency response
±0.5dB re 1004Hz, 300 to 4000Hz
noise
10dBrnCO maximum
envelope delay distortion
100 microseconds maximum, 400 to 3000Hz
peak/average ratio
greater than 98
I modem interface I
terminating impedance
4wire: 600 ohms ±10%, balanced, capacitively
coupled, both channels
2wire: 600 ohms ±10%, balanced, capacitively
coupled
franshybrid loss (2wire mode only)
ERL 45dB minimum
SRL LO 35dB minimum
SRL HI 35dB minimum
2wire return loss
ERL 28dB minimum
SRL LO 21dB minimum
SRL HI 28dB minimum
IlooPback specifications I
loopback-tone frequency detection
263DC wililoopback upon receipt of 2713 ±7Hz tone
(subject to level and timing specifications listed
below)
263DC
will not loopback upon receipt of tones
outside the range of 2713 ±37Hz.
loopback-tone level detection threshold
-30dBm
loop back tone duration
initiate: 1.6 seconds minimum, loopback after
removal of tone
release: 0.9 ±0.3 second maximum, release during
tone
tone loopback signa/-to-guard ratio
6dB minimum, 18dB maximum
optional release timeout period
20 minutes nominal aftertone-activation of loopback
loopback level
either 16dB (equal level) or 8dB loopback-path gain,
switch selectable
local de loopbaek
ground to operate, 2mA maximum
I common specifications I
lacility sealing current (Irom internal source)
20mA nominal
practice section 81263DC-1/81263DC-2/81263DC-3
input power
facility power: nominal 20mA sealing current or
56Vdc battery feed (maximum)
external power: either 18
to 26Vac at 7.5VA (this can
be supplied from commercial 120Vac by using a
Tellabs 8015 Transformer)
or -22 to -56Vdc at
30mA (maximum current comsumption)
operating environment
20' to 130'F (_7' to +54'C), humidity to 95%
(no condensation)
dimensions
height: 7.6 inches (1 g.3cm)
width: 6.7 inches (17.Ocm)
depth:
2.0 inches (5.0cm)
weight
1 pound 14ounces (850 grams)
mounting
wall-mounted; rubber feet are also provided for
desktop placement
7. testing and troubleshooting
7.01 The testing guide checklist in this section
may be used to assist in the installation, testing, or
troubleshooting of the 263DC-l, 263DC-2, and
263DC-3 DST Systems. The checklist is intended
as an aid in the localization of trouble to a specilic
unit. If a unit is suspected of being defective, a new
one should be substituted and the test conducted
again. If the substitute unit operates correctly, the
original unit should be considered defective and
returned to Tellabs for repair or replacement. We
strongly recommend that no internal (component-
level) testing or repairs be attempted on the unit.
Instead, a
malfunctioning unit should be returned
to Tellabs for repair or replacement as directed
below. Unauthorized testing or repairs may void the
unit's warranty. Also, if the unit is part of aregis-
tered system, unauthorized repairs will result in
noncompliance with Part 68 of the FCC Rules and
Regulations.
Note: Warranty service does not include removal 01
permanent customer markings on the covers 01
Tellabs products, although an attempt will be made
to
do so. II a unit must be marked defective, we
recommend that it be done on a piece 01 tape or on
aremovable stick-on label.
7.02 If a situation arises that is not covered in
the checklist, contact Tellabs Customer Service as
follows (telephone numbers are given below):
USA
customers: Contact Tellabs Customer Service
at your Teliabs Regional Office.
Canadian customers: Contact Tellabs Customer
Service at our Canadian
headquarters in Mississauga,
Ontario.
International customers: Contact your Tellabs
distributor.
US
central region: [phone]
US northeast region: [phone]
US southeast region: [phone]
US western region: (702) 827·3400
Canada: [phone]
page 13

practice section 81263DC-1/81263DC-2/81263DC-3
7.03 If aunit is diagnosed as defective, follow
the replacement procedure in paragraph 7.04 when
acritical service outage exists (e.g., when asystem
or acritical circuit is down and no spares are avail-
able). If
the situation is not critical, follow the repair
and return procedure in paragraph 7.05.
replacement
7.04 To obtain a replacement unit, notify Tellabs
via letter or telephone (see addresses and numbers
below)
or via TWX (910-695-3530 in the USA,
610-492-4387 in Canada). Be sure to provide all
relevant information,
including the 8X263DC-X part
number that indicates the issue of the unit in ques-
tion.
Upon notification, we shall ship a replacement
unit to you. If the unit in question is in warranty, the
replacement will be shipped at no charge. Pack the
defective unit in the replacement unit's carton, sign
the packing slip included with the replacement, and
enclose it with the defective unit (this is your return
authorization). Affix the preaddressed label provided
with the replacement unit to the carton being
returned, and ship the unit prepaid to Tellabs.
repair and return
7.05 Return the defective unit, shipment prepaid,
to Tellabs (attn: repair and return).
in the USA: Tellabs, Inc.
4951
Indiana Avenue
Lisle, Illinois
60532
telephone [phone]
in Canada: Tellabs Communications Canada, Ltd.
1200 Aerowood Drive, Unit 39
Mississauga, Ontario, Canada L4W 2S7
telephone [phone]
Enclose an explanation of the unit's malfunction.
Follow
your company's standard procedure with
regard to administrative paperwork. Tellabs will
repair
the unit and ship it back to you. It the unit is
in warranty,
no invoice will be issued.
test test
procedure
testing guide checklist
normal results
if normal conditions
are not met, verify:
transmit
level
transmit
channei
noise
receive
level
263DC-2
receive
equalization
Arrange transmit portion of
TMS, properly terminated at
600 ohms, for 1004Hz tone at
OdBm. Connect this signal to
XMT IN jack. Arrange receive
portion
of TMS for terminated
measurement at facility·side
port impedance selected on
unit, and connect it to pins TT
and TR on TBI. Vary LOSS set-
tings over their entire range.
Short OTT and OTR leads to-
gether either by inserting a
shorting plug into XMT IN jack
or
by strapping pins OTT and
OTR on TBI together. Connect
noise measuring test set to pins
TT and TR on TB1. Vary LOSS
settings over their entire range.
Remove short at xmt port. Ar-
range transmit portion
of TMS
for 1004Hz tone at -10dBm.
Set TMS xmt impedance to
match unit's facility-side ports.
Connect
TMS xmt to pins RT
and RR on TB 1. Arrange receive
portion
of TMS for terminated
measurement at 600 ohms and
connect it to RCV OUT jack.
Vary GN/LS controls over their
entire range.
Maintain
TMS connections as
described above. Transmit
2804Hz tone from TMS and set
equalizer switches to,in one at
atime.
Signal level
corresponds to
loss setting D.
Measured noise level is less
than 10dBrnCO for all loss set-
tings D. Noise level follows
loss setting D.
Signal level corresponds to
gain or loss setting D.
Level at RCV OUT jack increases
to
7.5dB above 1004Hz level
as equalization is added (O.5dB,
1.5dB, 3.5dB, 7.5dB) D.
page
14
Power O. Wiring D. Proper
impedance setting D. 516 set
properly
0.511 set properly D.
Unit not
in loopback D.
Xmt in port shorted D. Proper
termination impedances D. High
RF environment D.
Power D. Wiring D. Terminating
impedance 0.516 set properly
0.511 set properly D. Unit not
in loopback D.
Input level at 2804Hz same as
1004Hz D. Terminating imped-
ances correct D. Switch S 11
set correctly D.

practice section 81263DC-1/81263DC-2/81263DC-3
if normal conditions
test
test procedu re normal result
are not met, verify:
263DC-3
Maintain TMS connections as Level at RCV OUT
jack varies Terminating impedances
cor-
receive described in receive level test. with switch setting O. reet O. Switch
SII set
cor-
equalization Transmit 3400Hz tone and set
rectly O.
slope, HT, and BW switches to
various combinations.
receive
Short rev in leads together by Measured noise is less than
Rev in port shorted O. Proper
channel strapping
pinsRTandRRon TBI 10dBrnCO for all gain/loss set- terminating impedance O. High
noise together. Connect noise mea- tings D.
Noise level follows gain!
RF environment D.
suring test set to RCV OUT jack ioss settings O.
tone
Remove short at rev in port. Con· Loopback LED lights O. Mea-
Power D. Wiring D.Transmitand
iooback
nect rev portion ofTMS(properly suredtransmitlevel within ±1 dB receive
channels properly
terminated) to xmt out port, pins
of level specified on CLR O. aligned O. Loopback tone level
TT and
TR on TB 1. Arrange xmt
above-30dBm O. SwitchS15-2
portion
of TMS for 2713Hz out-
set properly O.
put at CLR-specified loopback
tone level at proper rev imped-
ance.
Connect this signal to rev
in port, pins RT and
RR on TBI;
after 2seconds change fre-
quency to 1004Hz and noteTMS
level reading.
tone Maintain test connections as
Loopback LED goes out O. Xmt in and rev in ports not
loopback described above and change
shorted O.
release frequency
to
2713Hz for
1
second.
timeout Place the DST unit in loopback
Loopback LED goes outin 20 ±1 S15-3 set to timeout position O.
loopback as instructed in tone loopback
minute D.
lest.
manual
Ground LOC LB. Arrange TMS Loopback LED iights O. Mea- Transmit and receive channels
loopback to send 1004Hz at specified suredtransmit levelwithin ±1 dB properly aligned O. Switch S15-
receive level and
at proper im- of specified level on CLR O. 1 set properly 0.
pedance. Connect this signal to
rev in port, pins RT and RR on
TBt. Arrange receive portion of
TMS for
appropriately termi-
nated
measurement and mea-
sure level at xmtout port, pinsTT
and TR on TBI.
page
15

'irtellabs
TellabS Incorporated
4951 Indiana Avenue, Lisle, Illinois 60532
telephone [phone]
twx 910-695-3530

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