ShoreTel and Cisco SPA112 - faxes, dropped calls

We have a new ShoreTel connect VOIP deployment (v21.84.5535.0). We are using Cisco SPA112 ATAs for some analog phones, faxes, etc...

We just figured out the resolution to our ATA being able to do 4 digit calls, but external calls would drop when you picked up the phone.

login to the ATA: Voice > Line1.

make the preferred codec 711 not 729. using the 711 codec fixed our issue. we also heard this is uncompressed and better for faxes so we are testing that.

FYI: G711 or G.711 is called called:
PCMA
PCMU

both are uncompressed.

Packet captures

Also a note on packet captures. Wireshark understands SIP and RTP really well. doing a packet capture of a SIP conversation will be useful even for the medium techie. after capture use this display filter: "sip or rtp". it works well.

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