One of my clients had a number of old Cisco CP-6941 phones that previously had been attached to a Cisco Call Manager. They wanted to use them on a new FreePBX system (FreePBX version 15.0.16.75 running Asterisk 16.13.0). As much as possible I wanted to use the GUI interface provided by FreePBX, instead of patching Asterisk or writing config files by hand. These instructions require purchasing the commercial Endpoint Manager module. The following worked for me.
1. Upgrade the phones from SCCP to SIP. I used SIP 9.4(1)SR3 downloaded from Cisco's website. I unzipped the files and used the Endpoint Manager Custom Firmware Managment Tool to upload them to Firmware Slot 2. This places them in a directory under the /tftpboot directory. Unfortunately, I was never able to get the phones to update using this configuration. So, I used the command line on FreePBX to copy the following files from /tftpboot/customfw/cisco to /tftpboot:
BOOT69xx.0-0-0-14.zz.sgn
DSP69xx.12-4-123-2.160199.zz.sgn
SIP69xx.9-4-1-3SR3.loads
SIP69xx.9-4-1-3SR3.zz.sgn
Then I created a file named XMLDefault.cnf.xml in /tftpboot whose entire contents are as follows:
<Default>
<loadInformation>SIP6900.9-4-1-3SR3</loadInformation>
</Default>
I set the DHCP server to pass out the IP address of the FreePBX server on both options 66 (Boot Server Host Name) and 120 (SIP Server). The SIP one probably isn't needed, but I didn't test it without. When the phones first boot, they will look for a config file via TFTP. If they can't fine one with their MAC address, they will look for XMLDefault.cnf.xml. This will cause them to load the new SIP firmware. Note that this will not work if they already have an extension configured for their MAC address, as they will see that file and never look for the generic one. After they are upgraded to SIP I used the Extension Manager to generate config files with all of their settings (see below).
2. Trial and error showed that PJSIP worked, while CHAN_SIP did not with this version of FreePBX and SIP firmware. Also, the extension password needed to be shortened as the phones would not accept a password of the default length. An 8 character password worked reliably, although I did not do enough testing to know what the maximum viable length is.
3. To create endpoints, I used the template for the CP7961G phone. Trial and error showed that this created a configuration file that was compatible with the CP-6941.
4. I wanted to be able to both call and intercom each extension. For my purposes, I was using three digit extensions. I created two extensions for each phone. 1xx calls the phone normally. 2xx intercoms the phone. To make this work right, I had to use Basefile Edit in the Endpoint Manager to customize the Cisco extension, adding the following addition:
File: enterprise
UA: 2autoAnswer
Parameter: autoAnswerEnabled
Value: 3
This added an entry to the second line on each phone that auto answered when that line was dialed. Then I created two entries for each device in the Endpoint Manager, setting Account 1 to be extension 1xx and Account 2 to be extension 2xx. This generated an XML file for each MAC address that had all the correct settings. I also added all the 2xx extensions to a page group, which allowed paging of all devices.
5. I did not get BLF working, as it looked to be a real pain, and I didn't really want to install an Asterisk patch that might or might not add additional problems.
