A less technical answer may help you get started. To use both voice and data on a T-1 you need an integrated T-1. In your case, 10 channels would be dedicated to voice and the remaining bandwidth will be your data. However, you may prefer a PRI. PRI delivers name & number but a T-1 can deliver number only. PRI uses the last channel for its data so 64K will be unavailable for V/D. A fax line can work over a T-1/PRI but many providers push a dynamic T-1 and faxes are unreliable on them. A dynamic T-1 is VoIP but does not require a VoIP system. SIP trunks do require a system with VoIP cards but does not necessarily have to be a 100% VoIP system.

- Dave S. -

You can never appease your ideologue opponents.