PULSECOM 4TOLB-3L1 User manual

Practice Section 1306
Issue 2, May 1992
1
Figure 1. 4TOLB-3L1 Channel Unit
with Loopback
Pulsecom
T
E
S
T
4TOLB-3L1
LB
®
D105177-1
REV A
ON
OFF
MAN
1. INTRODUCTION
This practice describes the Pulsecom
®
4TOLB-3L1 4-Wire, 600-Ohm Transmission Only
Channel Unit with Loopback, shown in Figure 1. Installation instructions and engineering
references are included.
Trademarks used in this manual:
CLEI is a trademark of Bellcore.
Pulsecom is a registered trademark of Hubbell Inc.
SLC is a registered trademark of AT&T.
The Recognized Component Mark is a registered trademark of Underwriters Laboratories Inc.
©1992 Pulse Communications Inc.All rights reserved.
CONTENTS PAGE
1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . 1
A. Reason for Reissue . . . . . . . . . . . . . . . . . . 2
B. Features . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. APPLICATIONS . . . . . . . . . . . . . . . . . . . . . . . . 3
3. INSTALLATION AND ALIGNMENT . . . . . . . . . 4
A. Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
B. Connections . . . . . . . . . . . . . . . . . . . . . . . . 7
C. Adjustments . . . . . . . . . . . . . . . . . . . . . . . . 7
4. CIRCUIT DESCRIPTION . . . . . . . . . . . . . . . . 11
A. VF Transmit Operation. . . . . . . . . . . . . . . 11
B. VF Receive Operation . . . . . . . . . . . . . . . 16
C. Loopback Circuit. . . . . . . . . . . . . . . . . . . . 16
5. SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . 17
6. MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . 17
7. CUSTOMER SERVICE. . . . . . . . . . . . . . . . . . 20
D4 CARRIER SYSTEM
4TOLB-3L1 4-WIRE, 600-OHM TRANSMISSION ONLY
CHANNEL UNIT WITH LOOPBACK
UL RECOGNIZED TELEPHONE EQUIPMENT
CLEI™ Code D4C0P885AA

4TOLB-3L1
1306, Issue 2, May 1992
2
A. Reason for Reissue
Document Reissue
This practice has been reissued to change the power specifications in Table 3 and to add
UL recognition.
Equipment Reissue
The 4TOLB-3L1 differs from the Pulsecom 4TOLB, 4TOLB-2, and 4TOLB-1L3 channel
units as shown in Table 1. The 4TOLB-3L1 also provides sealing current with single
switch selection of source/sink/off and improved current regulation over loop length in the
source mode. A –40 ° C to +85 ° C functional temperature range and switch selection of
loopback card-edge connector assignments allow use of the 4TOLB-3L1 in SLC
®
96
applications. The four units function the same in all other respects.
Table 1. 4TOLB Equipment Differences
A. LBTone,TRMT ATTN, and LB Gain
Model LB Tone Total Transmit Attenuation Loopback Gain
4TOLB-3L1 2713 Hz 32.5 dB ± 31.75 dB
4TOLB-1L3* 2713 Hz 31.75 dB 0,8,16 dB
4TOLB* 2713 Hz 24.0 dB 0,8,16 dB
4TOLB-2* 2400 Hz 24.0 dB 0,8,16 dB
B. TEK5/TEK6 and LB Lead Functions
Model
Lead Functions and Connector Pins
TEK5 TEK6 Local LB Local LB GND
4TOLB-3L1
a) D4/SLC 96 COT
b) SLC 96 RT 46 52 48 49 45 25 19 23
4TOLB-1L3*,
4TOLB*, and
4TOLB-2*
45 46 48 19
*Manufacture discontinued.

3
4TOLB-3L1
1306, Issue 2, May 1992
B. Features
The channel unit provides the following functional features:
•
4-wire voice-frequency (VF) transmission with DC isolation
•
Attenuation in the transmit (TRMT) and receive (RCV) paths selected with DIP
switches to compensate for variations in transmission levels
•
Front-panel maintenance-access connector (MAC) with bifurcated contacts
•
Loopback (LB) circuit with three-way LB activation: local, manual, or tone
•
Sealing current source/sink available with power-up ZAP (source mode)
•
Loopback gain/loss selectable from 0 to 31.75 dB in 0.25-dB steps
•
Can be used in the Pulsecom PD4 or PSC-96 channel bank
•
Can be used in the AT&T D4 or SLC 96 channel bank
•
Conductive front panel grounded to the frame
•
UL recognized
2. APPLICATIONS
The channel unit provides a 4-wire 600-ohm interface between a D4 or SLC 96 channel
bank and a 4-wire VF transmission facility with no DC signaling.An active loopback
circuit with an LB tone frequency of 2713 Hz is included. The LB circuit allows remote or
local testing of the 4-wire facility.
The unit can also be used on tandem carrier circuits utilizing end-to-end single-frequency
(SF) signaling. Figure 2 shows a typical application.
Figure 2. 4TOLB-3L1 Typical Application
T1
R1
T
R
DATA
STATION
TERMINATION
LB
X
F
M
R
RCV
ATTN
X
F
M
R
X
F
M
R
TRMT
ATTN
X
F
M
R
LB
G/L
LB
RELAY
LB
4TOLB-3L1
D4 CHANNEL BANK
T1
R1
T
R
DATA
STATION
TERMINATION
OFFICE A
D4
CHANNEL
BANK
OFFICE B
4ETO
T1
LINES
(1.544
MHz)
CUSTOMER
SITE

4TOLB-3L1
1306, Issue 2, May 1992
4
3. INSTALLATION AND ALIGNMENT
WARNING
This unit includes components that are susceptible to damage from static
electricity. DO NOT handle units without protection from electrostatic
discharge (ESD).
CAUTION
1. When replacing older 4TOLB units, reconnect loopback function leads
on the backplane. See Table 1.
2. Use a 325A power converter unit if a 48-channel bank is to be filled
with 4TOLB-3L1 plugs.The standard power module may not be able to
supply sufficient +12V power.
A. Options
General
The following options provided by the unit allow flexibility of application. These options
are selected by setting switches on the pc board and front panel. Switch locations are
shown in Figure 3. Detailed information for switch selection is given in Table 2.
Figure 3. 4TOLB-3L1 Switch Locations
.1 .2 .4 .8 1 2 4 8 16
TRMT ATTN S2S1
IN
.25 .5 1 2 4 8 16 G
IN
GAIN (G) / LOSS (L)
S8
S7
.1 .2 .4 .8 1.5 3 6 12
IN
RCV ATTN S3S4
S6
RT
D4/COT
SEALING CURRENT
S5
SINK SRCOFF
IN
S9
20 MIN TONE
4
NOTE: UNITS ARE SHIPPED WITH ALL ATTENUATION SWITCHES SET TO THE IN POSITION.
L

5
4TOLB-3L1
1306, Issue 2, May 1992
Table 2. 4TOLB Switch Options
Option Switch Designation (Note 1) S1 S2 S3 S4 S5 S6 S7 S8 S9
Name Function .1 .2 .4 .8 1 2 4 8 16 12 6 3 1.5 .8 .4 .2 .1
OFF SINK SRC D4/COT
RT .25 .5 1 2 4 8 16
G/L TONE 4/20 MIN
Transmit
Attenuation
(Note 2)
0.1 dB I O O O O O O O O
0.2 dB O I O O O O O O O
0.4 dB O O I O O O O O O
0.8 dB O O O I O O O O O
1.0 dB O O O O I O O O O
2.0 dB O O O O O I O O O
4.0 dB O O O O O O I O O
8.0 dB O O O O O O O I O
16.0 dB O O O O O O O O I
Receive
Attenuation
(Note 2)
12.0 dB I O O O O O O O
6.0 dB O I O O O O O O
3.0 dB O O I O O O O O
1.5 dB O O O I O O O O
0.8 dB O O O O I O O O
0.4 dB O O O O O I O O
0.2 dB O O O O O O I O
0.1 dB O O O O O O O I
Sealing
Current Off X
Sink X
Source X
Channel
Bank Type D4/COT X
RT X
Loopback
Gain/Loss
Amount
0.25 dB I O O O O O O
0.5 dB O I O O O O O
1.0 dB O O I O O O O
2.0 dB O O O I O O O
4.0 dB O O O O I O O
8.0 dB O O O O O I O
16.0 dB O O O O O O I
Loopback
Gain/Loss Gain (G) X
Loss (L) X
LB Tone
Activation
w/Timer
Deactivation
4 Min.
Deactivation I O
20 Min.
Deactivation I I
No Tone LB No Tone 0 I
NOTE 1: I = IN switch position (toward the arrow or letter designation);O = OUT switch position (against the arrow or letter designation);X = Set switch toward
required label.
NOTE 2: The added attenuation in the path is the sum of the values of all switches in the IN position.

4TOLB-3L1
1306, Issue 2, May 1992
6
Attenuation
Up to 32.5 dB of attenuation in 0.1-dB steps for the TRMT path and up to 24 dB of
attenuation in 0.1-dB steps for the RCV path can be selected. TRMT attenuation is
selected at switch blocks S1 and S2; RCV attenuation is selected at switch blocks S3
and S4.
Sealing Current
Switch S5 allows selection of three sealing current modes for the channel unit:
1) In position S5-SRC, the unit provides a momentary current surge (ZAP current) and
then maintains a constant lower-level current through the T/R and T1/R1 cable pairs;
the ZAP current flows automatically when the unit is inserted into the channel bank.
The ZAP current and constant sealing current are used to assure good contact at all
cable splices by removing any high-resistance film caused by oxidation.
2) In position S5-SINK, the unit provides a circuit closure between the T/R and T1/R1
cable pairs; this selection allows current provided by equipment on the metallic side to
flow through the cable pairs.
3) In position S5-OFF, no sealing current will flow through the T/R and T1/R1 cable
pairs.
Mounting
Switch S6, which routes the TEK5,TEK6, and LOCAL LB leads to their proper card-edge
connector pins, is selected based upon the type of channel bank into which the unit will be
placed. Select the D4/COT option if using a D4 bank or a SLC 96 central office terminal.
Select RT if the bank is a SLC 96 remote terminal. Note that SLC 96 banks must be
configured to Mode 3 (special services).
Loopback Gain/Loss
This option allows loopback gain or loss selection from 0 to 31.75 dB. Gain or loss is
selected to maintain the transmission level point (TLP) levels during loopback. The
amount of gain or loss as well as the GAIN/LOSS selection is set at switch blocks S7 and
S8. Switch settings are selected as shown below.
1) Compare the TRMT input and the RCV output levels. If the TRMT level is greater
than the RCV level, select the gain (G) option; otherwise, select loss (L).
2) Subtract the TRMT level from the RCV level and take the absolute value. Round this
value to the nearest 0.25 dB. This number is the value of gain/loss to be selected.
For example, if the RCV TLP has been set to +3.5 dBm and the TRMT TLP to –10 dBm,
then the loopback gain/loss is set to the L position, and +3.5 – (–10) = 13.5 dB of loss is
selected.

7
4TOLB-3L1
1306, Issue 2, May 1992
Loopback Activation Options
The loopback circuit can be activated by one of three methods:
1) Tone Activation—Requires placement of the pc board S9-TONE switch to the IN
position and reception of the LB tone.
2) Manual Activation—Requires placement of the front-panel MAN switch to the ON
position.
3) Local Activation—Requires connection between the LOCAL LB lead (pin 45 for
D4/COT or pin 25 for RT) and the LOCAL LB GND lead (pin 19 for D4/COT or pin
23 for RT).
Loopback Time-Out
This option allows selection of the time-out interval. Set switch S9 to the 4 position for
four minutes or to 20MIN for 20 minutes. After a tone loopback activation, a second tone
should be received to deactivate the LB circuit. The timer will return the unit to the
normal, non-loopback condition if the reset tone is not received within the time-out
interval.
B. Connections
All connector pin functions are detailed in Figure 4. Connections to a prewired D4
channel bank are identified. SLC 96 connections are also shown.
The unit is a Pulsecom Type D4 plug-in module. It occupies a 1.5-inch wide mounting
space in a standard Pulsecom PD4, AT&T D4, or equivalent channel bank; see Figure 5A.
The unit can also be installed in a Pulsecom PSC-96,AT&T SLC 96, or equivalent channel
bank; see Figure 5B.
C. Adjustments
General
Alignment of the channel unit consists of selecting the desired functions by setting pc
board option switches to the appropriate positions. The procedure for selecting the
switches may be either a “prescription” or a verified “in-line” alignment.

4TOLB-3L1
1306, Issue 2, May 1992
8
Figure 4. 4TOLB-3L1 Card-Edge Connector Pin Functions
(REAR VIEW)
CARD-EDGE
CONNECTOR
PREWIRED
D4 OR SLC 96
CHANNEL BANK
CONNECTIONS
T
-12V
12G
+12V
5G
TWD
TSP(N)
TSQ(N)
RSP(N)
RNDIS
PREWIRED
D4 OR SLC 96
CHANNEL BANK
CONNECTIONS
TPAM
TPAMG
+5V
RWD
RSQ(N)
RPAM
RPAMG
FGND
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
54
53
52
51
CUSTOMER
INTERFACE
CONNECTIONS
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
26
27
TNEN
T1
FG
-48 F
R
R1
LOCAL LB
SG
LOCAL
LB GND
TEK 5
TEK 6
TEK 6
TEK 5
LOCAL
LB GND
LOCAL LB
-48 SP
*
*
*
*
†
†
†
†
CUSTOMER
INTERFACE
CONNECTIONS
LOOPBACK CONNECTIONS FOR D4 (OR SLC 96 COT) BANK.
LOOPBACK CONNECTIONS FOR PSC-96 OR SLC 96 RT BANK.
†
*
NOTE: MAKE INTERNAL LB CONNECTIONS TO LEADS MARKED EITHER
† OR *, BASED ON BANK CONFIGURATION, BUT NOT BOTH.

9
4TOLB-3L1
1306, Issue 2, May 1992
A. 4TOLB-3L1 Installed in a Pulsecom PD4 or AT&T D4 Channel Bank
B. 4TOLB-3L1 Installed in a Pulsecom PSC-96 or AT&T SLC 96 Channel Bank
Figure 5. Location of the 4TOLB-3L1 in Pulsecom or AT&T Channel Banks
SHELF
COMMON UNITS
(INSTALL AS SHOWN
FOR MODE 3)
B1
B2
A1
A2
PCU OIU TPU
RU LIU-3 ACU TU
RU TU
PDU
ACUBLANK
1 2 11
23
11 12
24
DIGROUP B
DIGROUP A
INSTALL THE 4TOLB-3L1
IN ANY OF THE 48
CHANNEL UNIT SLOTS
13 14
1 2
13 14
24
23
12
COMMON UNITS
(INSTALL AS SHOWN
FOR MODE 3)
PU DLU TRU
SSU CTU LIU TRU
ACU
LSU
LIU TRU
1 2 3 4
PU TRU
LIU
MXU
MXU
TWO-SHELF
GROUP
TWO-SHELF
GROUP
INSTALL THE 4TOLB-3L1
IN ANY OF THE 48
CHANNEL UNIT SLOTS
12 CHANNEL UNITS
(24 SUBSCRIBER CHANNELS)
12 CHANNEL UNITS
(24 SUBSCRIBER CHANNELS)
12 CHANNEL UNITS
(24 SUBSCRIBER CHANNELS)
12 CHANNEL UNITS
(24 SUBSCRIBER CHANNELS)
SHELF D
SHELF C
SHELF B
SHELF A

4TOLB-3L1
1306, Issue 2, May 1992
10
Prescription Alignment
This procedure consists of selecting the desired switch positions. Figure 3 shows the
location of the switches; Table 2 provides option selection instructions.
1) TRMT and RCV Attenuation—Each attenuation switch on the pc board is marked
with an attenuation value in dB, which is added to the circuit when the switch is
placed in the IN position. Set the option switches to the desired positions
corresponding to the transmit/receive attenuation and gain/loss values. TheTRMT and
RCV attenuation functions and the appropriate TLP values are shown in Figure 6. The
proper attenuation values are selected as shown below.
a) To determine the proper TRMT attenuation value, first identify the input TLP and
then apply the following formula: TRMT Attenuation = Input TLP + Insertion
Gain + 8.5 dB. For example, with an input TLP of 0 dB, the TRMT attenuation
would be 0 + 7.5 dB + 8.5 dB = 16 dB.
b) To determine the proper RCV attenuation value, first identify the output TLP and
then apply the following formula: RCV Attenuation = +4 dB + Insertion Gain –
Output TLP. For example, with an output TLP of 0 dB, the RCV attenuation
would be 4 dB + 3 dB – 0 = 7 dB.
2) Channel Bank Type, LB Mode, and Sealing Current—Select these options by placing
the switches to the proper positions. See Figure 3, Table 2, and section 3A.
Verified In-Line Alignment
This procedure uses a transmission measuring set (TMS) such as the H.P. 4937A, the
front-panel TEST jack of the unit, and MAC jack to bantam jack adapter, such as the
Pulsecom B105097 or equivalent.An extender card can be used to provide easy access to
Figure 6. 4TOLB-3L1 Level Settings
17
- 8.5 dB
TLP
+4 dB
TLP
TRANSMIT PATH
TRMT ATTN =
INPUT TLP + 16 dB
RCV ATTN =
7dB - OUTPUT TLP
RECEIVE PATH
+7 dB to
-17 dB TLP
P/O J1
P/O J1
TRMT
+7.5 dB
+3 dB
0 to
32.5 dB
S1 & S2
3 9
0 to
24 dB
S3 & S4
TO
CHANNEL
BANK
+16.5 dB to
-16 dB TLP
RCV
T
R
0 to
±31.75 dB LOOPBACK
PATH
LB
LB