February 14, 2018 09:13 ET
Glad to hear from you. Thanks for the insight into my project.
Using phones that are no longer supported (product End-of-Life) by cisco is not helping my cause. Fortunately, cisco has released just one more release of software (Feb 14, 2017) for these old “cisco Unified IP Phones” (v9.4(2)SR3 in both SCCP and SIP). These “antiques” do support SIP with some exceptions: The phones do not support “intercom”. The hardware is just not there (based on the cisco product support guides). FreePBX EndPoint Manager does offer direct support of the cisco phones using SIP. Title bar on phones (what FreePBX is calling “Display Name”) only supports up to 11 characters. In cisco Call Manager, the “Display Name” is used for numbers only (extension number or like). And the “secret” to register the phone only supports 31-characters, not 32. IP Phones that I have working: 7941G, 7945G, 7962G and 7975G, all with SIP.
I am in total agreement that MGCP is a “dying” protocol. I am working to get to SIP. At this point it is a matter of vendor support for our old T1 line (which runs a total length of 6 inches before turning back into an IP stream) and the reconfiguration of the cisco 2921 gateway.
The “old” intercom system (more antique) I am still trying to trace lines. The core system is an outdated (with “wire wrap” terminals) that requires a device with RS-232 communications (requires a RS-232 null-modem cable, running WinXP, virtualized RS-232 via USB is NOT supported (Win versions Win7 or newer)). The system is a Rauland-Borg Telecenter System 21 which also doubles for the “Bell System” (start-end of class “bells”). Of course POTS might be the issue. I will look further into that. The system is accessed via cisco Call Manager (v9.4) thru a cisco router 2921 serial port (internal route/end point: AALN/S0/SU2/0@CGHSNC_Voice_GW.cghs.crusaders).
Again, thanks for the insight. Any help is welcome.
More research on my part is still needed.
Senior Network Engineer
Digitz Computers – Raleigh, NC
…on site at Cardinal Gibbons High School