Tecpro AD903

Auxiliary Input and Output Adaptor

The AD903 2 to 4 wire adapter allows connection of almost any audio source to a Tecpro ring intercom 2 wire system. For example, most broadcast video cameras have in-built 4 wire comms systems which are cabled within the main video cable. Use of an AD903 at the camera control unit will allow that camera to appear as a part of the Tecpro communication system, while minimising extra wiring and expense.

AD903 2 to 4 wire adapter

Product Description

The AD903 will work with most separate send and receive communications systems in the same way. Levels are totally independently adjustable on input or output.

Other applications include injection of microphone or line level external inputs onto the comms system, and the connection for external equipment such as recorders, radio links, audio consoles or paging systems to listen to the comms system.


  • Input and output on 4-wire side are transformer balanced, isolated and floating - reduces likelihood of hum and interference
  • Very wide input and output ranges - will interface to mic or line level systems
  • Sidetone null adjustment to minimise input to output cross talk
  • All presets are multiturn types for easy adjustment
  • Industry standard XLR type connectors


Technical Specs
Power requirements 24-30v DC at 15mA from comms system
External input -60 to +30dBu into 10k ohm nominal, balanced and floating
External Output -60 to +18dBu into 10k ohm nominal source, balanced and floating
Connections 4 wire via XLR 4 pin male
Intercom ring (2-wire) via XLR 3 pin male and female (loop-through)
Controls Mic/line switches and 10 turn presets to external system input and output
Sidetone null: 10 turn preset
Dimensions 107 x93 x50mm
Weight 420g
Construction Black anodised extruded case with glassfilled nylon bezels for protection
Accessory cable 'Y' lead YL908 has 4 pin female XLR splitting to one male and one female 3 pin XLR, for 4 wire connection.