Telebyte Products » Short Haul Modems / Line Drivers » Model 681/682

Model 681/682 - HDSL modem

***This item is legacy, please contact us for additional information, used, reconditioned or replacement products are often available***


  • T1/E1 transmissions rate
  • Lowest Cost
  • Full Duplex
  • 12,000 feet
  • 2B1Q Signaling
  • Higher data reliability
  • Applications
  • High Speed Local Loop
  • Lan-to-Lan Connections
  • Internet Access
  • Distributed Networks

(Model 681)

Product Description

The Model 681 for T1 and the Model 682 for E1 provide high speed transmission of synchronous data over distances greater than 12,000 feet with an exceptionally high degree of data reliability. This is accomplished by using 2B1Q signaling technology. Real life networks are not ideal but the 2B1Q line code reduces crosstalk and allows signals to be transmitted over much longer distances without repeaters or the removal of bridge taps. Since no conditioning of transmission lines is necessary when HDSL is used the Model 681/681 represents a plug and play solution for using copper lines for high speed data transmission and Internet access.

Equipment setup can be performed from the front panel using the LCD display and cursor controls or via a DB-9, RS-232 based, supervisory port on the rear of the HDSL modem. Use of the supervisory port does not require the LCD or the front panel switches. Setup includes the ability of configuring the device as a HTU-C or a HTU-R, initiating loopbacks and performing noise margin tests. The setup is stored in non-volatile memory and used as the default setup when the device is repowered. The setup can be changed at any time and the new setup becomes the default.

The diagnostic capability of the Model 681/682 includes both local and remote loopback tests. In addition to the loopback tests the device has the ability to perform a noise margin test on the real line. The results of this test are a digital representation of the received signal level.

The Model 681/682 is installed at both ends of a data link providing T1 (1.544 MBPS) or E1 (2.048MBPS) digital connectivity on two pairs of 22 gauge unconditioned copper wires over a distance of up to 3 miles. The data interface is V.35 and implemented on a conventional DB-25 connector. Telebyte offers low cost extension cables that provide the conversion from DB-25 to M block, 34 pin connector required for V.35 equipment.

Model Description Price Product Info
681 HDSL modem (T1) Contact Bomara

Specifications Manual Application Note

682 HDSL modem (E1) Contact Bomara

Specifications Manual Application Note

CAB 435 Male V.35 to Male DB-25 Contact Bomara


CAB 436 Female V.35 to Male DB-25 Contact Bomara


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