We have a cisco 2621 with faxes on fxs ports using MGCP. Code is V12.2.2.XA4. PSTN gateway H323 and is on a different 2621 - V12.2.6a. Faxes are not very reliable and sometimes only a few pages are sent before it drops. Also, sometimes incoming faxes are received several times because the calling fax think it has dropped.
Anyone any ideas? Would I be better using H323 rather than MGCP?