I have a Cisco 8851 on multiplatform firmware and trying to get Call Park programmed to one of the line keys. My call park pool is 301-305. I’ve configured the line key as follows:
For some reason, Asterisk strips the call park code from Cisco telephone default park key for that, thus it never gets the command to park the call.
You will have to somehow program a custom key to do that. Seems you have to send the command Asterisk is looking for in the custom key. I was about to work on that last year, but it got delayed.