Chapter 3 Managing Cisco SIP IP Phones
Modifying the Phone’s SIP Settings
3-10
Cisco SIP IP Phone 7960 Administrator Guide
78-10497-02
•
dtmf_inband—(Optional) Whether to detect and generate in-band signaling 
format. Valid values are 1 (generate DTMF digits in-band) and 0 (do not 
generate DTMF digits in-band). The default is 1. 
•
dtmf_db_level—(Optional) In-band DTMF digit tone level. Valid values are:
–
1 (6 db below nominal)
–
2 (3 db below nominal)
–
3 (nominal)
–
4 (3 db above nominal)
–
5 (6 db above nominal)
The default is 3.
•
dtmf_outofband—(Optional) Whether to generate the out-of-band signaling 
(for tone detection on the IP side of a gateway) and if so, when. The Cisco 
SIP IP phone supports out-of-bound signaling via the AVT tone method. 
Valid values are:
–
none—Do not generate DTMF digits out-of-band.
–
avt—If requested by the remote side, generate DTMF digits out-of-band 
(and disable in-band DTMF signaling), otherwise, do not generate 
DTMF digits out-of-band.
–
avt_always—Always generate DTMF digits out-of-band. This option 
disables in-band DTMF signaling.
The default is avt.
•
dtmf_avt_payload—(Optional) Payload type for AVT packets. Possible range 
is 96 to 127. If the value specified exceeds 127, the phone will default to 101.
•
timer_t1—(Optional) Lowest value (in milliseconds) of the retransmission 
timer for SIP messages. The valid value is any positive integer. The default 
is 500.
•
timer_t2—(Optional) Highest value (in milliseconds) of the retransmission 
timer for SIP messages. The valid value is any positive integer greater than 
timer_t1. The default is 4000.
•
timer_invite_expires—(Optional) The amount of time, in seconds, after 
which a SIP INVITE will expire. This value is used in the Expire header field. 
The valid value is any positive number, however, we recommend 180 seconds. 
The default is 180.