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RS232 Passive Splitter - DB25, 3-Port

Passively share one RS232 DCE device with three RS232 DTE devices.


280 In Stock
1 Year Double Diamond™ Warranty (Standard)

*Required field

Product Features

  • MASTER port is configured DTE and PORTS 1–3 are configured DCE
  • Signals present on the MASTER connector at pins 1, 3, 5, 6, 7, 8, 15, and 17 are sent to the corresponding pins on each of the PORT connectors.
  • Signals present on the PORT connectors at pins 2, 4, and 20 are passively stored and sent to the corresponding pins on the MASTER connector.
  • The total combined length of all cables connected to the unit should be less than 50 feet (15.2 m).
  • Data coming into the MASTER port on pin 3 of the RS232 DB25 Passive Splitter goes to all three Slave ports since they are all tied common.
  • Only one SLAVE port may transmit data to the MASTER port at any one time, Pin 2 on the three SLAVE ports are not tied in common and are isolated from each other by an OR gate.


Use our Modem Splitter to connect three terminals to one modem and save money—you won't need extra modems and extra lines!

No special cables are needed. It uses ordinary straight-pinned cables for hookup, and includes a 6-ft. DB25 male/DB25 female extension cable and a serial DB9 female/DB25 male AT adapter.

The Modem Splitter is transparent to speed and protocol, and works equally well in sync and async environments.

The TL073A-R4 includes (1) modem splitter, (1) 6-ft. DB25 male/DB25 female extension cable, and (1) serial DB9 female/DB25 male AT adapter.

A 6-Port Modem Splitter is also available. See "Similar Products."

Tech Specs

Connectors (4) DB25 F
Dimensions 7.5"H x 2.5"W x 1.3"D (19.1 x 6.4 x 3.3 cm)
Interface RS-232 (master port DTE, slave ports DCE)
Leads Supported Pins 1–8, 15, 17, 20
Main Channel Interface DTE
Protocol Synchronous or asynchronous
Subchannel Interface DCE
Weight 2 lb. (0.9 kg)
Product Includes:
  • (1) modem splitter
  • (1) 6-ft. DB25 male/DB25 female extension cable
  • (1) serial DB9 female/DB25 male AT adapter

  • Product works with: Extended-Distance Data Cables, 25-Conductor If you need port contention or advanced features such as prioritized port scanning, see our RS-232 Data Sharers (TL601A-R2) or our Programmable Sharing Device (TL304A) featured in the "Related Items" below.

    * 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 3-Port RS232 DB25 Passive Splitter 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.