Yes. We often mix long distance SIP trunks with local SIP trunks. By least-cost routing long distance calls over the long distance trunks, you save the maximum amount of money.
Note: With Broadvox, you must purchase three minimum of any flavor of SIP trunks. If you wanted to purchase their long distance (GoAnywhere) and local (GoLocal) products, you would need three minimum of each.
Yes, most SIP providers support G.711 or T.38 faxing protocols. We’ve been told that faxing over SIP trunks is about 95% reliable. For this reason, we generally recommend that our customers keep faxing off SIP trunks and on analog lines (which is great for a back-up line anyway). This may change as we feel more comfortable with it.
No. We have many customers that use an Integrated Access Device (IAD) that converts the SIP trunks back to traditional analog or PRI connections.