Datasheet

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Table 3. Voice Features of the Cisco SRP500 Series
Feature Description
Voice gateway
SIP version 2 (RFC 3261)
SIP messages via UDP/TCP
Echo cancellation (G.167 and G.168)
Dynamic jitter buffer
Simple traversal of UDP through NAT (STUN) (RFC 3489)
SDP (RFC 2327)
RTP/RTCP over UDP
3-way conferencing
Dual-tone multifrequency (DTMF) tone detection and generation
Voice activity detection (VAD)
Silence suppression
Comfort noise generation (CNG)
Caller ID generation and detection (frequency shift keying [FSK] and DTMF)
Media loopback
SIP Transport Layer Security (TLS)
Support for 2 simultaneous voice or fax calls per port
International
Telecommunications
Union (ITU) standard
voice codecs
Voice algorithms
G.711 (a-law and µ-law)
G.726-32
G.729a
Telephony interface
signaling support
Ring voltage: 40 to 90 Vpk
Ring frequency: 20 to 25 Hz
Voice features
Secure calling
Call forwarding: no answer/busy/unconditional
Call transfer
Call waiting/hold/retrieval
Three-way conferencing
Caller ID number and name (primary line and on call waiting)
Caller ID block (prevents sending out the caller ID)
Anonymous call blocking
Distinctive ringing
Do not disturb setting
Repeat dialing on busy
Call return
Emergency call support
Dial plan
Speed dial
Auto-attendant
Meet-me conference
Voice port interfaces 2 FXS ports, 1 relay FXO port (520 models); 4 FXS ports, 1 active FXO port (540 models)
Fax and modem
Fax and modem pass-through: Allows fax and modem traffic to pass through a voice port.
T.38 fax relay, including V.17, V.21, V.27ter, and V.29 and fax pass-through (pulse code modulation
[PCM]) (T.38 support is dependent on fax machine and network/transport resilience)