I’ve posted a few of these just for mental storage as well as making a public point that should be easily searched for when you’re racking your brain on why something doesn’t interoperate properly.

Here’s the latest;

NEC’s 8000 series PBXs that “support” SIP will fail to respond to Asterisk SIP/200 OKs after they place a INVITE if the asterisk UserAgent string contains at least parenthesis or dashes.

E.g:

sip.conf / [general]

useragent=asterisk-(11.7.0)

Will cause the NEC to fail to respond correctly to SIP/200

instead use something like:

useragent=11.7.0