I have a 2821 router with a VIC2-4FXO for incoming/outgoing calls to the mobile telephone network (numbers the kind of 6........) calling through Nokia Premicell lines, and a PRI for landline calls (915983270 is the main PRI number).
Incoming calls are immediately answered by the router, and the caller hears a white background noise mixed with a new ring tone until ephone with configured dn 22 answers.
When the user with dn 22 answers, his voice is mixed with the noise and somewhat muffled.
No problem with outgoing calls.
The relevant configuration is:
voice translation-rule 1
rule 1 // /915983270/
voice translation-profile default
translate called 1
translation-profile incoming default
dial-peer voice 1002 pots
incoming called-number 915983270
no register e164
ephone-dn 22 dual-line