Overview

The Dual Interface Configurations allow two ACC interface cards to be connected to a one mux panel/cable. In order for the interface ports to be accessed, they must be configured as LOOPBACK from one interface card, and as RS232, X.21 (or whatever is appropriate) from the other interface card.

In order to pass control of a given interface port from one mux card to the other, all of the activity on the given port must be terminated, the port must then be put into LOOPBACK mode by the interface card that is relinquishing control and into the appropriate (RS232, X.21, etc.) mode by the interface card that is taking over control.

In the case that the system that is currently controlling the mux panel or cable panics, there must be a way for the distressed system to relinquish control of the panel/cable. This is done by using the watch daemon and by using the MONITOR protocol module. The watch daemon sends heartbeats to the MONITOR protocol module. In the case that the protocol module on the card no longer receives a heartbeat from the daemon, it halts the card and places all ports into tri-state (loopback) mode.

It is suggested that the watch feature always be used when dual interface configurations are used.

The watch daemon logs its messages to the ZCOM message log. Refer to the ACC Error Guide for its error messages.