Hi Islam,

Integrations with Multiple Phone Systems

Depending on the version, Cisco Unity can be integrated with two or more phone systems:

•Cisco Unity 4.0 and 4.1 can be integrated with a maximum of two phone systems at one time. For information on and instructions for integrating Cisco Unity with two phone systems, refer to the Dual Phone System Integration Guide at

http://www.cisco.com/univercd/cc/td/doc/product/voice/c_unity/integuid/multi/itmultin.htm

•Cisco Unity 4.2 and later can be integrated with two or more phone systems at one time. For information on the maximum supported combinations and instructions for integrating Cisco Unity with multiple phone systems, refer to the Multiple Phone System Integration Guide at

http://www.cisco.com/univercd/cc/td/doc/product/voice/c_unity/integuid/multi/multcu42.htm

For Unity 4.2;

Maximum Number of Simultaneous Integrations for Each Phone System Type

SCCP

9

SIP

1

Circuit-Switched via Voice Cards

1

Circuit-Switched Phone System via Intel PIMG

9

For example, Cisco Unity can be integrated with the following phone systems at one time (a total of seven phone system integrations):

•Three circuit-switched phone systems through PIMG units

•Two Cisco Unified CallManager phone systems through Skinny Call Control Protocol (SCCP)

•One circuit-switched phone system through voice cards

•One Cisco Unified CallManager phone systems through SIP trunk

From this excellent doc;

Multiple Phone System Integration Guide for Cisco Unity 4.2

http://www.cisco.com/en/US/docs/voice_ip_comm/unity/401/integration/guide/multcu42.html#wp1223294

Hope this helps!

Rob