Please refer to Technical Specifications for a complete service guide.
Codecs Supported (SDP media attribute):
G.711 Ulaw (0)
G.711 Alaw (8)
DTMF tones (101)
G.729a (18)
Flowroute takes a unique approach to deliver call audio: via Direct Media. RTP media on your calls is delivered directly from your equipment to a peering network’s media gateway on the PSTN.
Read more about Direct Media in this KB article.