Black Box V.35 FOLD-ST Series User manual

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SUPPORT
INFORMATION
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Mail order: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018
Web site: www.blackbox.com • E-mail: [email protected]
FEBRUARY 1998
ME522A-ST
ME522AE-ST
ME522A-SM
ME522AE-SM
V.35 FOLD—ST
V.35 FOLD—SM
V.35 FOLD
RTS CD TD RD PWR
DLB TEST

2
V.35 FOLD
FEDERAL COMMUNICATIONS COMMISSION
AND
INDUSTRY CANADA
RADIO FREQUENCY INTERFERENCE STATEMENT
This equipment generates, uses, and can radiate radio frequency energy
and if not installed and used properly, that is, in strict accordance with the
manufacturer’s instructions, may cause interference to radio communication.
It has been tested and found to comply with the limits for a Class A
computing device in accordance with the specifications in Subpart B of
Part 15 of FCC Rules, which are designed to provide reasonable protection
against such interference when the equipment is operated in a commercial
environment. Operation of this equipment in a residential area is likely to
cause interference, in which case the user at his own expense will be required
to take whatever measures may be required to correct the interference.
Changes or modifications not expressly approved by the party responsible
for compliance could void the user’s authority to operate the equipment.
This digital apparatus does not exceed the Class A limits for Radio noise emission from
digital apparatus set out in the Radio Interference Regulation of Industry Canada
Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les limites
applicables aux appareils numériques de la classe A prescrites dans le Règlement sur le
brouillage radioélectrique édicté par Industrie Canada.
TRADEMARKS
ST®is a registered trademark of AT&T.
Any other trademarks mentioned in this manual are acknowledged to be the property
of the trademark owners.

3
V.35 FOLD
1. Specifications .....................................................................................4
2. Introduction........................................................................................6
3. Installation and Configuration .......................................................7
3.1 Opening the V.35 FOLD ............................................................7
3.2 Speed ...........................................................................................7
3.3 Transmit Data Clock...................................................................9
3.4 Carrier—Constant/Switched .....................................................9
3.5 RTS/CTS Delay.........................................................................10
3.6 Full or Half-Duplex Operation ................................................11
3.7 Final Installation Procedures ...................................................11
4. Monitoring Operation ....................................................................12
5. Diagnostics and Troubleshooting.................................................13
5.1 Simple Problems .......................................................................13
5.2 Diagnostic Tests ........................................................................13
5.3 Troubleshooting .......................................................................14
6. Fiberoptic Considerations .............................................................15
6.1 Link Distance ............................................................................15
6.2 Handling Fiber Optic Cable.....................................................15
Appendix A: V.35 Pin Assignments........................................................16
Appendix B: Tail-Circuit Applications ..................................................17
Contents

4
V.35 FOLD
Speed — 2.4 to 256 Kbps
Interface —
Terminal: V.35 DCE
Line: Multimode fiberoptic, graded index
Pins Supported —
V.35: CTS, DCD, DSR, ETCA, ETCB, FG, RCA, RCB,
RDA, RDB, RTS, SG, TCA, TCB, TDA, TDB
Fiberoptic: TX, RX
Range — 2.3 km (1.4 miles) with 100µ, -5dB/km fiber
optic cable;
1.5 km (0.9 miles) with 62.5µ , -5dB/km fiber
optic cable;
Connectors — (2) fiberoptic: SMA (905) female or ST
female;
(1) DB25S (25-pin sub D female) pinned per
EIA530A. A DB25-to-V.35 (female M-block)
adapter cable is included.
Fiber Optic Characteristics:
Wavelength — 820nM
Receiver Sensitivity — -21.7dB
Launch Power — -10.1 dB into 100µ cable
(typical) -14.1 dB into 62.5µ cable
-19.6 dB into 50µ cable
Operation — Point-to-point
Mode — Full or half-duplex; synchronous
Clocking — Internal, external, or recovered
Carrier — Constant or Switched
1. Specifications

5
V.35 FOLD
Loopback — Digital
RTS/CTS Delay — 0, 11, 50, or 175 ms
Protocol — Transparent
Indicators — 5 LEDs (TX, RX, RTS, CD, and PWR)
Diagnostics — DLB and Test Pattern Generator
Operating Temperature — 32° to 122°F (0° to 50°C)
Storage Temperature — -4° to 158°F (-20° to 70°C)
Humidity — 15 to 90% relative humidity, noncondensing
Mean Time
Between Failures — approximately 100,000 hours
Power — Wallmount transformer 115-VAC, 60 Hz, 8VA
or 230-VAC, 50 Hz, 8VA
Size —
Standalone: 1.8" H x 5.5"W x 8.5"D
(4.6 cm x 14.0 cm x 21.6 cm);
Rackmount: 4.7"W x 7.4"D (11.9 x 18.8 cm)
Weight —
Standalone: 1.5 lb. (0.7 kg);
Unit and transformer: 2.2 lb. (1.0 kg);
Rackmount: 0.5 lb. (0.2 kg)

6
V.35 FOLD
The V.35 FOLD (Fiber Optic Line
Driver) provides short-haul
synchronous data communication
over your own fiberoptic cable in a
point-to-point application. You must
use these units in pairs.
The FOLD is equipped with two
rear-panel adapters, either SMA
or ST®.
The FOLD has two fiberoptic ports
and a V.35 port (configured as DCE)
that connects to a host computer or
terminal (DTE).
Transmission can be half- or full-
duplex. The switch-selectable baud
rates range from 2400 to 256,000 bps.
LEDs on the front panel indicate
flow control. TX, RX, and RTS
indicate data activity on the V.35
interface only. CD indicates that
there is a carrier signal on the RX
fiberoptic connector.
Two pushbuttons on the front panel
(TST and DLB) make diagnostics
easy to use.
Internal switches or jumpers
determine these characteristics:
• Speed
• Carrier: constant or switched
with selectable RTS/CTS delay
• Operation: full- or half-duplex
• TX data clock select
Your FOLD package should include:
• the base unit with attached A/C
cord and power transformer,
• a DB25-to-V.35 adapter, and
• this manual.
If any of these items are missing,
check with your sales or technical
representative to get replacements.
2. Introduction
Mainframe
Fiberoptic Cable
Controller
V.35 FOLDV.35 FOLD
V.35
Cable
(EYN450)
V.35
Cable
(EYN450)
Figure 1. The V.35 FOLD is designed for a point-to-point application.

7
V.35 FOLD
3.1 Opening the V.35 FOLD
1. Remove the screw located at the
center of the bottom cover.
2. Remove the top cover.
3.2 Speed
The ten standard available speeds
are: 2.4, 4.8, 9.6, 19.2, 38.4, 56, 64,
112, 128, and 256 Kbps. The factory
setting is 56 Kbps.
Set the speed of the V.35 FOLD by
configuring DIP Switch banks S4 and
S5. See Figure 2 for switch-bank
locations. See Table 1 for how to set
the switches.
NOTE: Off in Table 1 corresponds to Open
on DIP switches S4 and S5.
If you are resetting the speed switch
banks after the V.35 FOLD has been
on, the heat sinks nearby might be
quite warm. This is normal because
of power dissipated in V.35
transmission.
Important
Both V.35 devices and both
V.35 FOLDs must be set to
the same speed.
3. Installation and Configuration
Table 1. DIP Bank Speed Settings
Bank Switch Speed (in Kbps)
2.4 4.8 9.6 19.2 38.4 56 64 112 128 256
4 1 On On On On Off Off Off Off Off Off
4 2 Off On On Off Off Off Off Off Off Off
4 3 Off On Off Off Off Off Off Off Off Off
4 4 On Off Off Off Off Off Off Off Off Off
5 1 On On On On On On On Off Off Off
5 2 Off Off Off Off Off Off Off On On On
5 3 On Off Off Off Off On On Off Off Off
5 4 On On On On On Off Off Off Off Off
5 5 On On On On On On On On On Off
5 6 On Off Off Off Off On Off On Off On
5 7 On On On On On On On On On On
5 8 On On On On On On On On On Off

8
V.35 FOLD
P1
S3
S4
S5
W3
W2
ABCDE
OPEN
1234
HALF FULL
OPEN
1234
O
F
F
12345678
Figure 2. Circuit Board Layout for the V.35 FOLD.

9
V.35 FOLD
3.3 Transmit Data Clock
Data timing is synchronized among
all connected devices in one of three
ways:
• Internal Clock (factory setting)
• Recovered Clock
• External Clock
DIP switch S3 controls the selection
of the clock timing. See Table 2 for
DIP switch settings. The fourth
switch position on DIP switch S3 is
unused. Figure 2 shows where the
DIP switch is located on the ciruit
board.
I NTERNAL C LOCK
The FOLD generates Transmit Data
clock and presents clock to the
attached DTE on TCA and TCB. The
DTE then presents synchronized
data to the FOLD on pins TDA and
TDB.
R ECOVERED C LOCK
The Transmit data clock presented
to the DTE is synchronized with the
timing of data received from the
remote device.
E XTERNAL C LOCK
The local DTE determines clocking.
The clock is presented to the FOLD
on Pins ETCA and ETCB, and
returned as TCA and TCB.
M ASTER C LOCK
To create a master clock, one of the
FOLDs should be set to internal or
external clocking and the other
FOLD set to recovered clock.
3.4 Carrier—Constant/Switched
Jumper W2 is used to select Constant
Carrier or Switched Mode. See
Figure 2 for the jumper’s location on
the printed circuit board. This
option determines how the FOLD
reacts to an RTS signal from the
local V.35 device. The FOLD is
defaulted to Contant Carrier Mode.
C ONSTANT C ARRIER M ODE
Place jumper W2 over position E.
The FOLD functions as if the
attached V.35 device is constantly
asserting RTS:
• The fiberoptic transmitter is
always on, and the FOLD’s CTS
signal remains high. Any data
sent by the attached V.35 device
is automatically transmitted by
the FOLD.
• The RTS indicator on the
FOLD’s front panel will always
be on, regardless of the data
activity on the V.35 interface.
The CD indicator on the remote
FOLD will remain lit.
Table 2. Clock Settings
Data Clock Switch
1234
Recovered On Off Off On
Internal Off On Off On
External Off Off On On

10
V.35 FOLD
Warning
Constant Carrier Mode will work
with full-duplex operation only,
not half-duplex. In Constant
Carrier mode the RTS signal is
constantly held high, preventing
any other signals from being
raised in the sequential fashion
required by half-duplex operation.
S WITCHED M ODE
Set the jumper block over one of the
four RTS/CTS delay positions. See
3.5 RTS/CTS Delay.
The FOLD transmitter is not
activated until the attached V.35
device asserts RTS. (Unlike Constant
Carrier Mode, this mode does not
always hold RTS high.)
When the attached V.35 device raises
RTS, the RTS indicator on the local
FOLD will light. The remote FOLD’s
CD indicator will also light,
indicating that a transmission link
has been established.
Once the local V.35 device drops
RTS, the local RTS and remote CD
indicators will go out.
3.5 RTS/CTS Delay
In Switched mode, you may insert a
delay after the V.35 device raises
RTS. This will delay the return of
CTS from the FOLD to the V.35
device.
This feature is useful in applications
that require time for the remote
V.35 device to prepare to receive
data. The local V.35 device should
not attempt data transmission
without sensing CTS.
In half-duplex operation, the
RTS/CTS delay is useful because it
allows time to establish which FOLD
will have control of the line in order
to transmit data.
RTS/CTS Delay Options
(Jumper W2):
Position D: 0 msec (no delay)
Position C: 11-msec delay
(factory setting)
Position B: 50-msec delay
Position A: 175-msec delay

11
V.35 FOLD
3.6 Full or Half-Duplex Operation
Figure 2 shows the location of
Jumper W3. This jumper allows you
to select half-duplex or full-duplex
operation. The factory setting is full
duplex.
3.7 Final Installation Procedures
• Replace the top cover.
• Replace the screw.
• Connect your fiberoptic cable to
the V.35 FOLD. When using SMA
connectors, tighten the
connection with your fingers and
then stop. Do not over-tighten.
• Connect the DB25-to-female
M-block connector to the V.35
FOLD. Connect the other end
to your V.35 device.
• Plug the power supply into an
AC outlet. The V.35 FOLD is now
ready for operation.
Figure 3. The rear panel of the V.35 FOLD.
TX RX

12
V.35 FOLD
The front panel of the Line Driver
has five status indicators (LEDs):
TD Lights when the TDA/TDB
circuit pair is active on the
FOLD’s V.35 port.
RD Lights when the RDA/RDB
circuit pair is active on the
FOLD’s V.35 port.
RTS Lights when V.35 device raises
RTS to request data
transmission.
In Constant Carrier mode the
RTS LED will always be on.
In Switched mode the RTS
LED will be on only if RTS is
asserted.
CD Indicates the presence of
carrier signal at the RX
fiberoptic connector.
If the remote V.35 FOLD is in
Constant Carrier Mode, the
local V.35 FOLD’s CD LED
will always be on.
If the remote V.35 FOLD is in
Switched Mode, the local V.35
FOLD’s CD LED will light
when the remote device
asserts RTS.
PWR Shows that the FOLD is
receiving AC power.
4. Monitoring Operation

13
V.35 FOLD
5.1 Simple Problems
Check for the simple problems first:
Are both FOLDs receiving AC
power? (Check the PWR LED.) Are
any there any cables that are not
properly connected? These are
obvious but often overlooked
problems.
5.2 Diagnostic Tests
Test configurations are set up by
using the front-panel pushbuttons.
These tests should be performed
when the FOLD is first installed or if
a problem occurs.
TST
The TST pushbutton enables the
V.35 FOLD’s transmitter circuitry.
The transmitter sends null data to
the remote V.35 FOLD. If the link is
operating properly, the RD indicator
on the remote FOLD receiving this
pattern will remain off. This
indicates that the remote V.35 FOLD
is correctly receiving and decoding
the null data.
If you press the TST button on both
the local and remote FOLDs, both
RD indicators should go off. This
ensures that both directions of the
link are in working order.
The RD indicator may flash before
switching off entirely. This is normal.
If the RD indicator remains lit or
flickers, see
Section 5.3, Troubleshooting.
DLB
Press the DLB pushbutton to initiate
digital loopback. Data received from
the RX fiber port is decoded, re-
encoded, and then transmitted back
to the sending FOLD. (See Figure 4.)
If you put the local V.35 FOLD in
TST and the remote FOLD in DLB,
you can judge the integrity of the
line by observing that the local RD
indicator remains off.
5. Diagnostics and Troubleshooting
DECODE
TDA, TDB RX
TX
V.35 FIBER
OPTIC
FIBEROPTIC
RECEIVER
FIBEROPTIC
TRANSMITTER
ENCODE
RDA, RDB
Figure 4. The DLB Test.

14
V.35 FOLD
5.3 Troubleshooting
Here are some problems to look for:
•Incompatible Baud Rates.
Remember that both V.35
FOLDs and their attached V.35
devices must all have the same
baud rate. Any incompatibility
will result in corrupt data
transmission.
•Incorrect V.35 Connections. Use
a BERT (Bit Error Rate Tester)
to verify that your V.35 devices
and the V.35 ports of the FOLDs
are functioning properly.
•Lead Mismatching. The TX
connector of the local FOLD
should be attached to the RX
connector of the remote FOLD.
Conversely, the RX connector
of the local FOLD should be
attached to the TX connector
of the remote FOLD.
•Maximum Link Distance. Check
the specifications to make sure
that the fiberoptic cable you are
running between the two FOLDs
has not exceeded the operating
range.
•Damaged Fiberoptic Cable. If
one direction of the link fails the
TST test, try reversing the leads
on both ends of the link. Repeat
the TST test on both FOLDs. If
the other direction of the link
now fails the test, the problem
is in the fiberoptic cable.

15
V.35 FOLD
6.1 Link Distance
The maximum transmission distance
is dependent on losses in the fiber
lines. The typical range for data
transmission is 1.4 mile (2.3 km)
using 100µ fiberoptic cable. The
distance with 62.5µ fiberoptic cable
is 0.9 miles (1.5 km). Actual
distances may be less and are
affected by the quality of the fiber
itself, connectors, and the terminus
connections.
6.2 Handling Fiber Optic Cable
• Treat connectors the same as
a fine camera lens.
• Clean the connectors with lens-
cleaning tissue before installing
them.
• Keep connectors covered with
not installed.
•Never use the connectors to pull
fiberoptic cable through
conduits.
• Do not pull fiberoptic cable
tightly around a corner. This can
cut transmission by up to 50%.
6. Fiberoptic Considerations
Figure 5. Fiber Optic Connectors
SMA
Connector
ST
Connector

16
V.35 FOLD
Appendix A
V.35 Pin Assignments
Lead Flow Name DB25 Pin M-block Pin
Transmitted data In TDA 2 P
TDB 14 S
TX data clock Out TCA 15 Y
TCB 12 AA
Received data Out RDA 3 R
RDB 16 T
Remote TX clock In ETCA 24 U
ETCB 11 W
Signal Detect Out DCD 8 F
Request to Send In RTS 4 C
Clear to Send Out CTS 5 D
Signal Ground In/Out SG 7 or 23 B
Protective Ground In/Out FG 1 A
Data Set Ready Out DSR 6 E
RX Data Clock Out RCA 17 V
RCB 9 X
RX data clock Out RCA 17 V
RCB 9 X

17
V.35 FOLD
Appendix B
Tail-Circuit Applications
In a typical FOLD tail circuit, the
FOLD will be connected back-to-
back with another DCE device
through the V.35 interface.
To create a tail circuit, set both
FOLDs for external clocking. Then
connect them with a cable that
crosses the Receive clock outputs
with the external clock inputs, and
omits the Transmit clock lines
(TCA and TCB). With TCA and TCB
omitted, there is no danger of
creating a short-circuit on those
leads and, in turn, increasing the
current that the unit will draw.
Host CPU
Fiberoptic Cable CSU/DSU
V.35 FOLDV.35 FOLD
V.35
Cable
(EYN450)
V.35 Tail
Circuit Cable
(EYN452)
CSU/DSU
Front-End
Processor
DDS Line
AA
BB
CC
FF
EE
HH
RR
PP
TT
SS
UV
VU
XW
WX
Figure 6. Cable pinouts for V.35
tail circuit applications.
Figure 7. V.35 FOLD tail-circuit application.

1000 Park Drive • Lawrence, PA 15055-1018 • 724-746-5500 • Fax [phone]
© Copyright 1998. Black Box Corporation. All rights reserved.