IP phones(78xx,88xx series) return SIP message 486 on declining call

[sourabh jain]

Hi Experts,

We have encountered the issue with Cisco MPP  (3PCC) phones, as these send SIP user busy message [sip:486] on declining call,

is there any configuration at device to change it to SIP 603 global reject cause ?,

Please guide,

[b.winter]

Hi,
AFAIK there is no possibility.

[sourabh jain]

I see in configuration under menu programmable Soft keys ,there is ringing key list, i.e. answer|1;ignore|2;ignoresilent|3; , i tried to add endcall instead of ignore , but it didn't work, any other keyword it supports?  that might change the behaviour

[TechLvr]

@sourabh jain 
When you decline a call while ringing, it always sends a "486 Busy here" message. I believe you cannot get the phone to send a 603 Decline message which usually means the call did not reach the intended recipient.

Also, per Cisco documents, "answer", "ignore", "ignoresilent" are the only keywords supported in the Ringing Key List. And ignore means decline here which triggers the "486 Busy here" message. If there is no voicemail or call forwarding configured on the phone extension, then the UC server passes the the busy message to the SBC (in case the calling party is external). 

[sourabh jain]

I found in some other manufacture IP phones support this feature (change in response code) in their configuration file as  "features.normal_refuse_code = 603" , i believe there might be something in Cisco phones configuration as well , else its good PRT to pursue with , please let me know if i missed anything such in Cisco phones

[TechLvr]

I don't think you missed anything. That configuration parameter does not exist for Cisco MPP phones according to the admin guide. 

https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cuipph/MPP/8800/english/admin-guide/p881_b_8800-mpp-ag/p881_b_8800-mpp-ag-11_chapter_01100.html#TPCC_RF_S11F1807_00