T38 FAX Cisco SPA122 Configuration

T38 FAX. Cisco SPA122 Configuration

How to enable T38 FAX support on Cisco SPA122 VoIP adapters.

Proxy and Registration


In  “Proxy and Registration” and “Subscriber Information” fill

Proxy: YourSIP.Server

User ID: SIP Username

Password: SIP Password



NAT Settings


Goto Voice –> Line 1 or Line 2 depending your lines configuration:

NAT Mapping Enable: Yes

NAT Keep Alive Enable: Yes



Supplementary Service Subscription


In the “Supplementary Service Subscription” turn off “Call Waiting” and “Tree Way Call”:

Call Waiting Serv: No

Three Way Call Serv: No



Audio Configuration


In the “Audio Configuration“:

Preferred Codec: G.711u or G.711a

Use Pref Codec Only: Yes

Silence Supp Enable: No

Echo Canc Enable: No

FAX Passthru Method: ReINVITE

FAX Enable T38: Yes

FAX T38 ECM Enable: Yes

FAX Tone Detect Mode: Calee only



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