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Sync Modem Eliminator - DB25 Female/Male

The Sync Modem Eliminator allows two synchronous RS-232 DTE (host) devices to communicate with each other without the need for expensive synchronous modems.


Limited Quantity In Stock
1 Year Double Diamond™ Warranty (Standard)

*Required field

Product Features

  • Emulates dialup or leased-line modem service.
  • Installs inline with RS-232 cable.
  • Supports data rates from 7 to 224 kbps, including 56 kbps.
  • Distances supported up to 75 feet (22.8 m) on either side of the connector.
  • Indicator LEDs display TX, RX, and CD.
  • Internal or external clocking. 


  • Runs at 38.4 kbps.
  • Operates full- or half-duplex.
  • Has two DB25 connectors and six LEDs (TX, CTS, and DSR for each of the two ports).

  • We've tailored our SME-4M for your IBM equipment. Use it to regenerate the RS-232 signals, so you can send data up to 100 feet (30.4 m). Then you can put your sync (or async) devices where you want them.

    Use the SME-4M to provide clocking to your system, instead of a pair of modems or line drivers to connect controllers or other systems to your front-end processor. You can monitor the operating status easily with a glance at the front-panel LEDs.

    Because the SME-4M is so small and lightweight, it minimizes logistics problems and simplifies installation and replacement in the field. No special tools are required either. It's definitely designed for do-it-yourself installation.

    Tech Specs

    Connectors (2) DB25 F
    Distance Up to 100 ft. (30.4 m) total
    Indicators (6) LEDs: TX, CTS, DSR for each of the two ports
    Interface RS-232
    Operation Full- or half-duplex
    Power 115 VAC, 60 Hz (230-VAC version on request)
    Protocol Synchronous or asynchronous
    Size 1.8"H x 5.5"W x 8.6"D (4.6 x 14 x 21.8 cm)
    Speed 38.4 kbps
    Weight 2 lb. (0.9 kg)
    This product works with:
  • RS-232 Cable, 25-Conductor, Male/Male (ECM25C)
    The ME251C-R3 works with:
  • 12-Card Rack (RM008).
    Questions? Contact our FREE Tech Support.

    * Technical specification weight is the unit weight. It is not the packaged shipping weight. For shipping weight, please contact Black Box customer service at 877-877-2269.

  • Support


    Double Diamond Warranty Diamond

    Double Diamond™ Warranty (Standard)

    Take the risk out of equipment purchases with the Double Diamond™ Warranty from Black Box Network Services.

    The Double Diamond Warranty is our warranty that protects your Black Box® brand products* from accidental damage, including drops, water, and power surges.

    The Sync Modem Eliminator - DB25 Female/Male comes with a standard 1 Year Double Diamond™ Warranty (Standard) already included.

    During the warranty period, Black Box Network Services will repair or replace your damaged equipment within one week of receipt at NO CHARGE!*

    Plus, get an Extended Double Diamond Warranty.

    You can also extend your warranty or protect a previously purchased Black Box® brand product** for an additional year—for only 10% of the purchase price! Or, extend your coverage for a full three years for only 20% of the purchase price!

    Ordering an extended warranty is easy: When viewing a product in your shopping cart, just select the one or three years of additional coverage in the dropdown menu under “Warranty Options.” For details, contact Customer Service at 724-746-5500.

    * Warranty subject to certain exclusions and limitations ** Certain products may not be eligible.

    What’s more, we also have a 45-day return policy. Simply call Customer Service for a Return Authorization (RA) number, return your product in new condition and in the original package, and receive a full refund.