Black Box ME1240A-F, ME242A-M, ME900A-M, ME900A-F Specifications

Interconnect sync equipment

without a modem.

Interconnect sync equipment

without a modem.

Sync Modem Eliminators—Nonpowered (SME-NPR)

© 2007. All rights reserved. Black Box Corporation.

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FEATURES

• Depending on the model, you can
transmit at speeds up to 19.2, 38.4,
64, or 224 kbps.

• All models emulate switched or
dedicated services and can transmit
in half- or full-duplex operation.

• Enable two RS-232 DTE devices to
exchange sync data without the need
for expensive synchronous modems.

• Easy to install and configure.

• Choose between high-speed and
standard models.

Choose this inexpensive alternative to a pair of sync modems.

OVERVIEW

Sync data transmission meets savings with our Synchronous
Modem Eliminators-Nonpowered (SME-NPR). They enable two
RS-232 DTE devices (terminals, PCs, mainframes, workstations,
etc.) to exchange sync data without the need for expensive
synchronous modems. Choose between high-speed or
standard models.

The RS-232 High-Speed Sync Modem Eliminator­Nonpowered (ME242A-M) supports six selectable rates, from
7 kbps up to 224 kbps. To emulate switched or dedicated
service, the delay can be set to either 0 or 6.6 ms.

Our standard RS-232 Synchronous Modem Eliminators­Nonpowered (ME1240A-F) are available with top speeds
of 38.4 kbps.

To emulate switched or dedicated service, the delay
can be set to 0, 6.6, or 53 ms.

The ME900A-M and ME900A-F are similar to the
ME1240A-F, with maximum speeds of 19.2 kbps.

All our Synchronous Modem Eliminators-Nonpowered
(SME-NPR) units derive their power from the RS-232 interface.
The SME-NPRs feature two male or female DB25 connectors.
In addition, these units can transmit in half- or full-duplex
mode.

All models feature tri-state LEDs to monitor receive data,
request to send, and data carrier detect on each side of the
device. The carrier can be configured as “constantly on”
or “controlled by RTS.”

For any questions on these or other BLACK BOX

®

products,

call our FREE Tech Support.

Synchronous Modem Eliminator—

Nonpowered 38.4 kbps, DB25

Female (ME1240A-F)

Host Computer

Controller

RS-232.

RS-232, also known as RS-232C and TIA/EIA-232-E, is a
group of electrical, functional, and mechanical specifications
for interfaces between computers, terminals, and modems.
The RS-232 standard was developed by the Electrical Industries
Association (EIA), and it defines requirements for connecting
data communications equipment (DCE)—modems, converters,
etc.—and data terminal equipment (DTE)—computers,
controllers, etc.) devices.

The standard, which is functionally equivalent to ITU
V.24/V.28, specifies the workings of the interface, circuitry,
and connector pinning. Both sync and async binary data
transmission fall under RS-232. Most PCs use the RS-232
interface to transmit data to modems, and some printers
even use it.

Although RS-232 is a “standard,” you cannot necessarily
expect seamless communications between two RS-232 devices.
Why? Because different devices have different circuitry or
pinning, and different wires may be designated to perform
different functions.

The typical RS-232 connector is DB25, but some PCs and
other data communication devices have DB9 connectors.
To connect 9-pin PC ports to devices with 25-pin connectors,
you need a simple adapter cable. The most commonly used
interface, RS-232 is ideal for transmitting data at speeds up
to 20 kbps and over distances up to 50 feet (15.2 m).

Technically Speaking

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TECH SPECS

DCD — Constantly ON or controlled by RTS (selectable per port)
Operation — Emulates point-to-point, half- or full duplex switched or

dedicated line

Ring Indicator — Constantly ON
RTS/CTS Delay — ME242A-M: 0 or 6.6 ms (selectable per port);

ME1240A-F, ME900A-M, ME900A-F: 0, 6.6, or 53 ms

(selectable per port)

Speed — ME242A-M: 7, 14, 28, 56, 112, or 224 kbps (selectable);

ME1240A-F: From internal clock: 1200, 2400, 4800, or

9600 bps; 19.2 or 38.4 kbps (selectable);

From external clock: 38.4 kbps;

ME900A-M, ME900A-F: 1200, 2400, 4800, or 9600 bps; 19.2 kbps

(selectable)

Interface — RS-232 synchronous
Connectors — ME242A-M, ME900A-M: (2) DB25 male;

ME1240A-F, ME900A-F: (2) DB25 female

Indicators — (2) Tri-state LEDs for Receive Data (RD), Request to Send

(RTS), and Data Carrier Detect (DCD)

Power — From the interface
Size — 1.2"H x 2"W x 5.3"D (3 x 5.1 x 13.5 cm)

Item Code

High-Speed Sync Modem Eliminator-Nonpowered

224 kbps, DB25 Male ME242A-M

Synchronous Modem Eliminators-Nonpowered

38.4 kbps
DB25 Female ME1240A-F

19.2 kbps
DB25 Male ME900A-M
DB25 Female ME900A-F

You might also need…

RS-232 Cable, 25-Conductor,

10-ft. (3-m) ECM25T-0010

(For other RS-232 cable lengths, call our FREE Tech Support.)

Modem eliminators.

Understanding the process of elimination.

If your office environment has sync equipment, and if that
equipment is also used for local data communications, you
should consider replacing those modems with cost-effective
and versatile modem eliminators.

What does a modem eliminator do?

One modem eliminator can connect a local terminal and
computer port in lieu of the pair of modems that they would
normally connect to. Plus, a modem eliminator enables
DCE-to-DTE data and control-signal connections that are
not easily achieved by standard cables or connectors in a
sync environment.

Basically, a modem eliminator simulates a sync data link.
It does this two ways. First, it provides clocking, which is
mandatory for sync devices to communicate. Second, it
provides the handshaking that DCEs do.

Three reasons to use a modem eliminator:

One—if you have two sync DTEs in the same room or close

to each other, you will need a modem eliminator.

Tw o— if you have a network with routers, you just found

the perfect equipment tester.

A modem eliminator can enable in-house bench testing
of routers or existing equipment. There’s no need to place
routers all over your network only to find out they don’t work
once you test the LAN. A modem eliminator tells you what
equipment passes your tests before you install.

Three—a modem eliminator makes good economic sense.
One does the job of two modems—and it does the job better.
You get a high return on your investment.

Technically Speaking

ME1240A-F