[asterisk-users] Interesting observation

[David Gibbons]

<snip>
My understanding is that Charter 'telephone' doesn't use IP at all but
rather uses some additional frequency spectrum on their cable network.
Hence, the reason why faxing with their service is reliable unlike other
providers who are *actually* using VoIP.
</snip>

I think what you're referring to is the general hesitance of the cable providers to call their phone service VOIP service. VOIP still has a negative connotation with most regular folks, so they don't want to negative PR.

I'm don't have any facts, but I'll bet you a penny that they don't have a proprietary system using something /OTHER/ than IP to send encapsulated voice over 'additional frequency spectrum'. That would be prohibitively expensive to develop and pointless from a technical standpoint, given that IP telephony is already set to deploy and relatively mature.

The reliability of faxing is based soley on network jitter and latency and codec compression. I've found that taking the compression out of the mix (using g.711 ulaw) and controlling the jitter and latency (something that's easy to do on a private network like theirs with QOS) causes faxing to be pretty darn reliable.

--Dave