V.35 is an International Telecommunication Union (ITU) Telecommunication Standardization Sector (ITU-T) specification originally standardized as an interface for 48 kbps line transmissions.
V.35 is a high-speed serial interface used for all line speeds that exceed 20 kbps. It supports higher data transfer rates (DTR) and connectivity between data communication equipment (DCE) and data terminal equipment (DTE) over digital lines.
The V.35 interface is located on layer 1 of the Open Systems Interconnection (OSI) model between network access devices and packet networks at DTRs exceeding 20 kbps. It uses bandwidths of numerous telephone circuits as a group. V.35 has balanced data and clock leads, and handshake leads are single-ended. It is commonly used for 56kbps and 64kbps data rates.
V.35 is recognized by a blocky 34-pin connector that combines the bandwidth of numerous telephone circuits to provide a high-speed interface between DTE and channel service units. It achieves better speeds and distance by combining balanced and unbalanced voltage signals on the same interface. Cable distances range up to 1200 m at maximum speeds of 100 kbps. Actual distance depends on equipment and cable quality.
Most local area network (LAN) routers are equipped with a V.35 electrical interface. V.35 plugs are standard, ranging from 20 mm-70 mm with built-in, hold-down gold-plated contacts and mating screws. However, the plug is too big to fit on add-in cards, such as those used by PCs.
V.35 also has special interface connector pin outs in M/34 male and female connectors. The different pins and their associated signals include A-chassis ground, B-signal ground, C-request to send, D-clear to send, E-data set ready, F-data carrier detect and V-Receive Timing A.
V.35 was discontinued and replaced with the V.10 and V.11 recommendations.
Read More »