AS2950 - 4W E&M Line Switching Unit
The AS2950 Line switching Unit provides a method of connecting two 4W E&M devices over any one of two E&M circuits.
This provides the facility with resilience to link drop out by ensuring that the links are routed in two different directions. Typically a primary and secondary link.
Under normal operation the unit continually monitors the condition of both links and signals an alarm condition appropriate to the connections. Communications will normally take place over the primary link and will fall back onto the secondary link under a failure of the primary. This fall back is completely automated with no break in communications. In addition to the standard backup facility the system has an EOW (Engineering Order Wire) port. This provides the engineer/user with the facility to create a callover the link as a full duplex call.
The handset unit (AS2970) has an interface module to condition signals to and from the handset and is also fitted with a buzzer and LED to indicate call conditions.
The unit can operate from any 24Vdc supply and in conjunction with the AS2960 shelf can be fitted with main and backup supplies for power fail resilience.
Unit size is standard Single Extended Eurocard, connections to line and equipment are via standard RJ45 connectors.