easiest way is to call your DID and see what key it rings on. then call from an internal xtn and check the key. if they are different you may have the subline outlined above.
if they are the same you may have a virtual forwarded to your extension.
to check you need to press in this order
trans, conf, *, Trans, conf, #
it should now say "cat mode'
press lnr or spd
now you will have "command=" on the screen
enter E600 (E is the 5 button on the top row or the first on the second row)
then press recall
enter 5262
press recall
so now you have on the phone
E600>5262>xxxx (Where XXXX is an extension number prolly 2262)
press speaker to step down if you want to see more. pick up then replace the handset to exit this mode.
Regards,
Dr VuDu