The RS422 system is a 4 wire balanced data connection between a Controller and a Device. Examples of Controllers are editors, graphics systems and a variety of control panels. Devices include VTRs, vision mixers, routing switchers etc. Normally, 9 pin D-type male connectors are used at each end of cables, with female connectors on the rear panel of both Controller and Device. The circuit comprises 4 signal wires (2 balanced pairs) plus signal and chassis earths. The earths, if both are used, according to convention may each be wired to two separate pins in the connector (4 pins in total). The ninth pin is not used.
There are 30,239 possible incorrect ways to connect the cable. Comtest detects all of these. It will also detect cable breaks, and faults in the Controller and Device ports. It shows whether data is passing from the Controller to Device and back. Two pairs of LEDs indicate that everything is working properly, or a fault exists. A logical sequence of tests will indicate the likely source of the fault condition.
Comtest is small, only 63 x 33 x 25mm. Engineers and technicians will find it indispensable, whether commissioning systems or in maintenance. Non-technical users will find it useful, in that they can readily identify the likely cause of failure, and consequently what best action to take.
Manufactured by Lynden Micros Ltd.