I recently purchased a Yealink T28 to evaluate as a suitable IP phone for use with Asterisk. Before I integrated it with Asterisk I had a play around with the standard SIP features and found a serious issue with the SIP registration.
The problem being that if you wanted to allocate an extension to the phone, it wouldn’t play ball. For instance for “register name” or “display name” settings the account 12345678 would work but 12345678*200 would not. Trying to configure it either via the browser interface or via the phone directly kept giving the message -
“If you are attempting to enter a string, this could contain an invalid character like $*%&#:!”
Yealinks website is pretty dire, with no technical information available. I eventually managed to get through to someone at Yealink and resolved the issue with firmware version 2.3.0.30. As the file isn’t generally available online, I have listed it here – Yealink T28 2.3.0.30 Firmware.
The Yealink T28 is a good phone, but is let down by their support. As an aside, if anyone has any info on using the XML features on this phone, please let me know.
