Polycom SIP 3.0.2 User Manual

Administrator’s Guide SoundPoint IP / SoundStation IP 

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Chord-sets are the building blocks of sound effects that use synthesized rather 
than sampled audio (most call progress and ringer sound effects). A chord-set 
is a multi-frequency note with an optional on/off cadence. A chord-set can 
contain up to four frequency components generated simultaneously, each 

with its own level.
There are three blocks of chord sets:

• callProg (used for call progress sound effect patterns)

• ringer

• misc (miscellaneous)
All three blocks use the same chord set specification format.

tone.dtmf.viaRtp

0, 1

1

If set to 1, encode DTMF in the active 

RTP stream, otherwise, DTMF may be 

encoded within the signaling protocol only 

when the protocol offers the option.
Note: tone.dtmf.chassis.masking should 
be enabled when tone.dtmf.viaRtp is 
disabled.

tone.dtmf.rfc2833Control

0, 1

1

If set to 1, the phone will indicate a 

preference for encoding DTMF through 

RFC 2833 format in its Session 

Description Protocol (SDP) offers by 

showing support for the phone-event 

payload type; this does not affect SDP 

answers, these will always honor the 

DTMF format present in the offer since 

the phone has native support for RFC 

2833.

tone.dtmf.rfc2833Payload

96-127

101

The phone-event payload encoding in the 

dynamic range to be used in SDP offers.