Echo on remote side from local analog (a/b) subscribers

[1064]

Hi to everyone!

We have an OXO with software ONEDE032/037.001.

We are using following telephony service:
a) SIP Trunk handled by OXO direct
b) SIP (via FritzBox) connected to OXO via ISDN
c) GSM (via coM.sat Gateway) connected to OXO via ISDN

On the local side we are using a mix of digital, DECT and analog phones.

We are experiencing echos on the remote side, whenever we are initiating a call from a local analog (a/b) subscriber to a remote site using the GSM Gateway.

We have tested:

digital to remote
a) no echo
b) no echo
c) no echo

DECT to remote
a) no echo
b) no echo
c) no echo

analog (a/b) to remote
a) no echo
b) no echo
c) echo

Any idea? Good suggestions welcome . Thanks!

[frank]

explain your a) b) c) please

[vad]

explain your a) b) c) please

a) SIP Trunk handled by OXO direct
b) SIP (via FritzBox) connected to OXO via ISDN
c) GSM (via coM.sat Gateway) connected to OXO via ISDN

[frank]

Did you switch the ISDN port to see if it follows the port of the gateway ?