I recently ordered a Nortel 1535 SIP phone as recommended by Ward Mundy here – http://nerdvittles.com/?p=703
At £35 (price seems to vary up and down) from e-bay they are definitely a bargin. There’s a good thread on the PBX-in-a-Flash forum about setting it up here – http://pbxinaflash.com/forum/showthread.php?t=8273
They come with the default language set to Turkish so that needs changing to English.
I also really struggled with a couple of things setting it up with my O2 router. By default the WiFi would not work and also it would not register with Asterisk.
Wifi not working
I have a O2 Wireless Box II and by default the Wifi security “WPA-PSK Version:” was set to “WPA+WPA2”. The phone would not connect to the WiFi until I set this to just “WPA2” (and entered the passphrase). Even then the WiFi setup on the phone is a bit flakey. Manually assigning the ESSID seems to help too.
Phone would not register with Asterisk
Even more tricky to track down was the fact that the O2 Wireless Box II tries to do something clever with SIP connections to port 5060. I had to telnet to the router (default address – 192.168.1.254) and remove the SIP settings.
To do this –
User = SuperUser password = O2Br0ad64nd
:connection unbind application=SIP port=5060
and then reboot the router. This information was taken from here – http://forum.o2.co.uk/viewtopic.php?t=1313
After that the phone would register following the setup directions in the PBX-in-a-Flash forum thread mentioned above.