Black Box ME251A-R3 User manual
Replaces a pair of modems to connect
IBM mainframes, minicomputers, and controllers.
Replaces a pair of modems to connect
IBM mainframes, minicomputers, and controllers.
Synchronous Modem Eliminator (SME-4M)
© 2007. All rights reserved. Black Box Corporation.
FREE 24-hour Tech Support: 724-746-5500
blackbox.com
2 of 3
FEATURES
• Replaces two modems in point-to-point
applications.
• Speeds up to 38.4 kbps.
• Small and lightweight. Easy to install
or replace in the field.
• LEDs show DSR, CTS, and TXD for
both ports.
• Front-panel switches set signals and
select test mode.
• Operates transparently, sync or async.
IBM compatibility at two different speeds. Runs sync or async, too!
OVERVIEW
The Synchronous Modem Eliminator (SME-4M) enables
a mainframe or minicomputer to communicate locally with
another mainframe, minicomputer, or remote controller.
And best of all, it saves you money because the SME-4M
replaces the two modems or line drivers normally needed
for such communication.
Just one versatile SME-4M enables asynchronous,
synchronous, or bisynchronous communications between
two DTEs over RS-232C cable.
In synchronous mode, the unit operates at data rates that
top out at 38.4 kbps. Plus the SME-4M operates transparently
in either synchronous or asynchronous mode. You can also
configure the SME-4M to operate at some nonstandard data
transmission speeds. To set the SME-4M for one of these
speeds, configure the unit according to the chart on the right.
The SME-4M is small and lightweight, so it’s easy to handle.
And because no special tools are needed, installation is simple.
The modem eliminator’s front panel has six LEDs and
three switches. The six LEDs indicate Clear To Send (CTS),
Transmitted Data (TXD), and Data Set Ready (DSR) for each
port. The three switches include Ring Indicator (RI) and
Control Data Set Ready (CON) signals, and (LB) selects the
Digital Loopback Test Mode.
Use the SME-4M’s diagnostic loopback capability to test
asynchronous applications. Simply press the switch and enter
data at the host terminal or computer. That data should
return to you exactly as you sent it.
The unit fits neatly on a desktop. Each SME-4M is shipped
with a 115-VAC power transformer and a user’s manual.
SME-4M
(ME251A-R3)
IBM®
mainframe
RS-232 Cable
(ECM25C)
RS-232 Cable
(ECM25C) S/3X or
AS/400®host
2/22/2007
#10205
724-746-5500 blackbox.com
Strap Position Transmission Rate (bps)
a 76,800
b 153,600
38,400 38,400
19,200 19,200
9600 9600
4800 4800
2400 2400
1200 1200
Crystal Frequency 2.4576 MHz
Buyer’s Guide Transmission Speeds
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TECH SPECS
Clock — Internal or external
Diagnostics — Bidirectional loopback (async)
Operation — Full or half-duplex
Protocol — Async or sync
Speed — 1.2, 2.4, 4.8, 9.6, 19.2, and 38.4 kbps
User Controls — (3) switches: Ring Indicator (RI), Control Data Set Ready
(CON), Digital Loopback Test Mode (LB)
Interface — RS-232
Connectors — (2) DB25 F
Indicators — (6) LEDs: DSR, CTS, TXD for each of the two ports
Power — 115 VAC/60 Hz, 10 watts
Size — 1.8"H x 5.5"W x 8.6"D (4.6 x 14 x 21.8 cm)
Weight — 2 lb. (0.9 kg)
Item Code
Synchronous Modem Eliminator (SME-4M) for RS-232
38.4-kbps
Standalone (115-VAC) ME251A-R3
For optimum performance and a 20% savings, order…
RS-232 Cable, 25-Conductor, 10-ft. (3-m) ECM25C-0010
2/22/2007
#10205
Recognize any of these situations?
• You wait more than 30 minutes to get through
to a vendor’s tech support.
• The so-called “tech” can’t help you or gives you
the wrong answer.
• You don’t have a purchase order number and the
tech refuses to help you.
• It’s 9 p. m. and you need help, but your vendor’s
tech support line is closed.
According to a survey by Data Communications
magazine, 90% of network managers surveyed say
that getting the technical support they need is extremely
important when choosing a vendor. But even though
network managers pay anywhere from 10 to 20% of their
overall purchase price for a basic service and support
contract, the technical support and service they receive falls
far short of their expectations—and certainly isn’t worth
what they paid.
At Black Box, we guarantee the best value and the
best support. You can even consult our Technical Support
Experts before you buy if you need help selecting just
the right component for your application.
Don’t waste time and money—call Black Box today.
Why Buy From Black Box? Exceptional Value.
Exceptional Tech Support. Period.
724-746-5500 blackbox.com
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