Larse TDSU-BV35 T1 Digital Service Unit A84-BV35A-102 Rev D V.35 RS449 DTE

Larse TDSU-BV35 T1 Digital Service Unit A84-BV35A-102 Rev D V.35 RS449 DTE

The Larse TDSU-BV35 is a T1 Digital Service Unit (DSU) designed to terminate a T1 line and provide a clean digital interface to customer data terminal equipment (DTE). Manufactured by Larse Corporation of Santa Clara, California, this unit carries assembly number A84-BV35A-102 Rev D and offers dual DTE interfaces — V.35 and RS449 — on its rear panel. It is a 1U rackmount chassis with a well-organized front panel for monitoring and control of T1 framing, loopbacks, and test patterns.

Specifications & What's Included

• Make: Larse Corporation (Santa Clara, CA)
• Model: TDSU-BV35
• Assembly / Part Number: A84-BV35A-102
• Hardware Revision: Rev D
• Type: T1 Digital Service Unit (DSU)
• Data Rate: 1.544 Mbps (full T1)
• Form Factor: 1U Rackmount
• Country of Manufacture: USA
• DTE Interface 1: V.35 (Winchester-style connector, rear panel)
• DTE Interface 2: RS449 (37-pin D-sub, rear panel)
• Line Interface: RJ-style LINE port (rear panel)
• Station Clock: BNC-style STATION CLOCK connector (rear panel)
• Front Panel LEDs: DATA, CLOCK, BUFFER, RED ALARM
• Front Panel Indicators: EQPT / LINE status, NEAR END / FAR END alarm
• Front Panel Controls: LOCAL/DTE switch, SET/RESET, FAR END SET, ONES/QRSS TEST selector, TRANSFRAMER RESET
• Monitor Jacks: LINE MON, LINE OUT, EQPT IN, EQPT MON (front panel)
• Unit powers on; CLOCK LED illuminates green on power-up

Applications

T1 Digital Service Units were used at the customer premises end of a leased T1 circuit to terminate the carrier's line and present a standard V.35 or RS449 DTE interface to routers, multiplexers, PBX systems, videoconferencing bridges, and similar CPE. The DSU handles line equalization, framing (D4/ESF), and loopback signaling required by the carrier, isolating the customer equipment from the raw T1 signal. Larse Corporation was an early and respected maker of T1 access equipment in the 1980s and early 1990s, a period when T1 leased lines were the standard high-speed WAN connection for enterprise and campus networks before the rise of Frame Relay and later broadband alternatives. The dual V.35 and RS449 interface capability on this model made it flexible for connecting a range of DTE equipment from different vendors. Units like this are still sought for legacy T1 infrastructure maintenance, lab testing, T1 simulation setups, and private network environments that continue to operate on T1 circuits.