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RS232 Line Sharing Device - 8-Port

Expand sync leased line, polled environments without adding computer sync ports or sync communications links.


Limited Quantity In Stock
Typically Ships within One Week
1 Year Double Diamond™ Warranty (Standard)

*Required field

Product Features

  • Increases network efficiency.
  • Transparent to data.
  • Fully cascadable.
  • Individual subchannel enable/disable switches.
  • It also generates internal timing signals or gets its clocking externally from subchannels
  • data rates up to 19.2 Kbps
  • Synchronous and asynchronous data transmission


The Programmable Sharing Device from Black Box enables four or eight sync terminals or modems to access an IBM® host via a single-host port connection.

It provides local clocking for on-site setups or external clocking for remote applications. Configure it to disable "active" ports that haven’t sent data for a predefined length of time or disable ports manually with the front-panel switches.

Flexible contention methods (RTS, DCD, or actual data signals) make the Programmable Sharing Device easy to use when the usual signals aren’t available.

Tech Specs

CE Approval Yes
Clock Internal or external (from DTE or DCE)
Connectors (5) DB25 F
Contention Type RTS/DCD control or data signals
Indicators Both: (1) ON/OFF, (1) for data broadcast from main channel to subchannels; TL304A: (4) for Channel Activity, (4) for Channel Disabled; TL305A: (8) for Channel Activity, (8) for Channel Disabled
Interface RS-232
Operation Synchronous or asynchronous
Power 115 VAC, 60 Hz, 10 watts (230-VAC version on request)
Size 1.7"H x 17"W x 8.2"D (4.3 x 43.2 x 20.8 cm)
Speed (Maximum) 19.2 kbps
Weight TL304A: 5.5 lb. (2.5 kg); TL305A: 4.4 lb. (2 kg)
This product works with:
Product works with:
  • Standard RS-232 Low-Noise Cable, 25-Conductor, Male/Male (ECM25T, ECM25C)
  • RS-232 Extended-Distance Cable, Male/Male (EDN25C-MM)
  • 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.



    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 8-Port RS232 Line Sharing Device 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.