[asterisk-users] help no ring on caller side

[Nhadie]

Hi,

Got this weird problem that the caller does not hear a ring.

The issue is it's specific to the local telco:

Using telco 1 (mobile), calls in to my DID, caller hears a ring and gets 
forwarded to voicemail if i did not answer.

Using telco 1 (landline), calls in to my DID, caller hears a ring and 
gets forwarded to voicemail if i did not answer.


But using Telco 2, my phone is ringing, caller does not hear a ring on 
his side, and i dont answer call hangs up instead of going to voicemail


where should i start tracing the problem? TIA

regards

nhadie