1
For sending sync or
async data.
2-wire, twisted-pair
operation.
Transmit speeds up to
38.4 or 128 kbps.
Distances up to
3.4 miles (5.5 km).
Full-duplex operation
using “echo
cancellation.”
Performs local analog
loopbacks and local
and remote digital
loopbacks.
Generates bit error
rate test patterns.
Isolation transformer
guards versus AC or
DC overvoltages.
T
he BLACK BOX
®
V.35 2-Wire
Short-Haul Modem provides a
simple way to send your data at
short distance over telco lines.
The modem operates full-duplex
synchronously over a single 2-wire
twisted pair, at selectable data
rates from 600 bps up to 128 kbps,
or asynchronously up to 38.4 kbps.
The short-haul modem
incorporates interface circuits
for the terminal or computer, an
adaptive echo-canceler, an
automatic adaptive equalizer, a
modulator, and a demodulator. The
adaptive equalizer provides noise
immunity and high performance
over low-quality lines.
The modem uses 2B1Q line
coding and provides an operating
range of up to 3.4 miles (5.5 km)
over 26 AWG twisted-pair wire—
no matter what data rate is used.
The modem also couples to the
telephone line through an isolation
transformer that protects against
AC or DC overvoltages.
The protection circuitry enables
the unit to survive even if DC is
connected to the line accidentally.
ASYNC/SYNC 2-WIRE SHORT HAUL
MODEM
DIG
ANA
PWR
RTS
TD
RD
DCD
LOS
ERR
TEST
REM
PATT
RESET
Send sync or async data up to 3.4 miles (5.5 km)
over your existing 2-wire twisted-pair lines.
Key Features
V.35 2-WIRE SHORT-HAUL MODEM
Full-duplex operation uses
echo cancellation. You need only
to set one modem to be a master
and the other to be a slave.
Internal DIP-switch controls
enable you to configure the V.35
2-Wire Short-Haul Modem to suit
your application. To reconfigure
the modem for a different type
of operation, just reposition the
switches.
The short-haul modem also
features diagnostic capabilities,
including local analog loopback
and local and remote digital
loopback. An operator at either end
of the link can test both local and
remote short-haul modems as well
as the line itself. Control loopback
with either the unit’s front-panel
pushbuttons or signals passed
through the DTE (PC, data terminal)
interface. Pressing the front-panel
Pattern button causes the local
short-haul modem to send the
remote unit a continuous Bit Error
Rate Test (BERT) pattern. By
performing these end-to-end tests,
you can ensure link integrity and
quickly find out which components
of your short-haul modem system
are operating properly and which
aren’t.
For monitoring and
troubleshooting purposes, the
short-haul modem has eight front-
panel LEDs that inform you of the
device’s operational status and
activity. At a glace, you can tell
whether the local and remote units
are in sync, when the RTS signal
from the DTE is high, when the
local unit is transmitting or
receiving data, when the modem
detects an error in the BERT
pattern, and more.
For your transmission line, we
highly recommend using twisted-
pair cable capable of supporting
high data rates, especially
Category 3 grade or better. For
DTE-side cable runs, use straight-
through-pinned cable that’s no
more than 25 feet (7.6 m) long with
an M/35 male connector for
plugging into the V.35 2-Wire
Short-Haul Modem.
NOTE:
Must be used in pairs.
Black Box Corporation
• 1000 Park Drive • Lawrence, PA 15055-1018 • Tech Support: 724-746-5500 •
www.blackbox.com
•
e-mail: [email protected]
© 2004. All rights reserved.
Black Box Corporation.
11/18/2004
#14072
