Cisco SRP521W-K9-G1 Administration Guide - Page 99

Configuring Voice Managing Caller ID Services 6 Optimizing Fax Completion Rates Issues can occur with fax transmissions over IP networks, even with the T.38 standard, which is supported by the SRP. You can adjust several settings on your SRP to optimize your fax completion rates. STEP 1 Ensure that you have enough bandwidth for the uplink and the downlink. • For G.711 fallback, it is recommend to have approximately 100 kbps. • For T.38, allocate at least 50 kbps. STEP 2 To optimize G.711 fallback fax completion rates, set the following on the Line tab of your SRP: • Network Jitter Buffer: very high • Jitter buffer adjustment: disable • Call Waiting: no • 3 Way Calling: no • Echo Canceller: no • Silence suppression: no • Preferred Codec: G.711 • Use pref. codec only: yes If you are using a Cisco media gateway for PSTN termination, disable T.38 (fax relay) and enable fax using modem passthrough. For example: modem passthrough nse payload-type 110 codec g711ulaw fax rate disable fax protocol pass-through g711ulaw STEP 3 Enable T.38 fax on the SRP by configuring the following parameter on the Line tab for the FXS port to which the FAX machine is connected: FAX_Passthru_Method: ReINVITE NOTE If a T.38 call cannot be set-up, then the call automatically reverts to G.711 fallback. STEP 4 If you are using a Cisco media gateway use the following settings: Cisco SRP500 Series Services Ready Platforms Administration Guide (SRP520 Models) 99