Can't hear some incoming calls

[Ansextra]

I have had a number of incoming calls that I cannot hear the remote caller.
This does not affect all calls but it seems as if they are calls originating from businesses rather than home phones.

I have the OBI202 set up with a static IP and in a DMZ on my router.
Additionally I have SIP ALG disabled.

Does anyone have any ideas on how I can solve this issue?  I keep thinking it may be a codec issue with businesses using IP Telephony but really don't know.

[FromNY]

Having the same problem.
Calling Google Voice provider on OBI110 from GV provider on OBI202 and we cannot hear each other. Tried to call from OBI110 to OBI202 with GV providers and we cannot hear each other either. When I called OBI202 and OBI110 from cell phones, connected successfully and we could hear each other.
Any suggestions?

[drgeoff]

I have had a number of incoming calls that I cannot hear the remote caller.
This does not affect all calls but it seems as if they are calls originating from businesses rather than home phones.

I have the OBI202 set up with a static IP and in a DMZ on my router.
Additionally I have SIP ALG disabled.

Does anyone have any ideas on how I can solve this issue?  I keep thinking it may be a codec issue with businesses using IP Telephony but really don't know.

Are these "proper"  calls or is your phone being rung by SIP scanners?

[Ansextra]

These are proper calls.  No SIP scanners involved.  When I call the numbers back the calls work fine.