We have a new Inter-tel Axxess system (v 8.200)

And Inter-tel SIPS IP Phones - model 8662.

They work fine on the LAN, but take them offsite ... we are coming into our site through MS ISA Server, we've opened all the ports that we think we need to, although we really aren't that sure ! The phone connects, we can dial an extension BUT get no voice either way ... any ideas ?

Anyone know definitely what ports the SIPS phones need ?

Thanks in advance

[This message has been edited by pauld (edited October 06, 2004).]