SIP Call Issue Troubleshooting Guide Content

SIP Theory


Brief Introduction of SIP and SDP Protocol



Understand the different scenarios of SIP call

Understanding Voice Transmission of Remote Extension

Check List for SIP Call Issues



- One-way audio & NAT related issue

Call Hangs up at 30 Seconds

The Router Settings Relevant with One Way Audio & 30 Seconds Call Hang up Issue

One-way Audio after Hold Retrieve from Cisco CUCM Extension

One-way Voice Issue when TA1610 Integrated with Cisco Cloud PBX


 - Internal, Inbound or Outbound Call Failure

Unable to Make Calls by TA FXS Ports - Invalid Caller ID Number Configured

Internal Call Failure - SRTP is not Enabled on the Phone

Incoming Call Failure - Caused by Default SIP Port 5060 on PBX Changed

Calls are Rejected by Cisco SPA122 - Caused by Auth INVITE in Cisco SPA122

Incoming call from SIP trunk gets '401 Unauthorized' - Caused by Wrong SIP Port on SIP Trunk Settings

Intermittent Call Failure when Using TkReg SIP Trunk

Failed to Make Outbound Call - INVITE Packet Size Larger than Router MTU Requirement

Failed to Make Calls from TE/TB to SIP trunk When Caller ID is Blank

Outgoing Call via Peer Trunk Failed - Wrong DOD number

Unable to Make Outbound or Inbound Calls through SIP Trunk - ACL Strategy on Provider Side

Call Transfer failed- Caused by the T.38 Option

SIP Trunk Status Unreachable - SIP Provider Didn't Respond the OPTIONS Packet from PBX

Outbound Call Failure when TA2410 Integrated with Mitel PBX

Unable to Receive Incoming Calls from the SIP trunk - Session Timer Required


- Call Drop or Call Hangup issue during active call

Call Dropping after 5 min via SIP trunk - Carrier Response 420 Bad Extension

Call Dropped after One Hour -Timeout Limit on Provider Side

Calls Drop after 12 Seconds - Abnormal SIP Contact from the other SIP Device

Calls Drop after One Minute - Caused by Extension Max Call Duration(s)


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