How to set callerid in Elastix Call Forward

Elastix allows an extension to setup call forward via feature code such as *72.  These codes are defined in PBX|Features.    When we dial from PSTN to an extension which has CF setup to external party, the call is forwarded using the foreign caller as CID.  As this call is not originated from an extension, it will be handled by a catch-all route which usually presents the company's primary number to the forward destination.  In most cases, we consider it intuitive.
In some cases, however, we prefer to handle the forwarded call differently such that it presents another CID.  It is useful if our Elastix PBX is sharing by different business entities (eg in a business center) because there is no such a common primary number.  The forwarded call should be handled by an extension-based outbound route.

The default Elastix behaviour must be modified not to use the foreign caller as CID when forwarding call.  Rather, the CID should be the extension being forwarded to select the appropriate outbound route.

The Elastix UI does not provide this option.  By changing the dialplan code in extensions_override_elastix.conf, we could manipulate the CID used in CF.


Redundancy Asterisk Configuration

Here describes a working solution to implement a redundant asterisk PBX system.

When we design a redundant PBX solution, it is intuitive to think of building two Asterisk nodes with some kind of synchronization mechanisms ranging from simple scripts to more complicated HA cluster.

The more challenging task is to failover the PSTN connection when the primary node is down.

The TwinStar solution from Xorcom is directly addressing this problem.

This solution is comprised of two Asterisk servers with identical configuration in active-standby mode and one Astribank channel banks for PSTN connection .

The Astribank provides FXO or T1 connection with telco provider. It communicates via USB with the two Asterisk servers and continuously monitors the function of the primary node. Upon detecting node failure, it instantly passes control to the backup server. This architecture ensures communication in the organization is re-established in short time.

Further information can be found in here