Guys, just to chime in--I deal with this issue a lot.
Nowadays, most cable providers are using these Arris TG series gateways to provide POTS to customers. All the Arris does is send the voice as data to the CMTS, and from there it is transported as SIP/VoIP.
More than once I've run into this issue and it has been a problem with the provider's VoIP infrastructure. It takes some major convincing to get them to look at it, but we can usually get it resolved.
EDIT: With SIP, the two endpoints talk to each other and negotiate a random port to transport audio on. If there is too much latency between the two endpoints, it can result in this behavior, or even one way audio.
Last edited by telecom guy10; 12/05/18 05:40 PM. Reason: Missing info
