IT Toolbox

3CX & VoIP

IP Telephony / SIP

3CX & VoIP

3CX and VoIP troubleshooting for SIP trunks, DECT, SBC, NAT, RTP, audio quality, certificates, phones and backups.

3CXSIPDECTSBCRTPNATVoice Quality

2BAOI modules

13selected resources

6definitions

Tools & diagnostics

Direct access to the most relevant BAOI modules for this technology.

Tool 3CX / VoIP Center

Open “3CX / VoIP Center” and the related IT Toolbox features from this tool.

Open → Troubleshooting SSL Center / Certificates / PKI

SSL/TLS analysis and diagnosis: expiration, SAN, certification chain, PEM, CSR, AD CS and troubleshooting commands.

Dictionary

Essential concepts related to 3CX & VoIP.

Dictionary SIP Dialog

A signaling or media element used in SIP-based VoIP communications.

View → Dictionary SRTP

A signaling or media element used in SIP-based VoIP communications.

View → Dictionary SIP URI

A signaling or media element used in SIP-based VoIP communications.

View → Dictionary SIP 480 Temporarily Unavailable

A signaling or media element used in SIP-based VoIP communications.

View → Dictionary SIP Redirect Server

A signaling or media element used in SIP-based VoIP communications.

View → Dictionary SIP Extension

A signaling or media element used in SIP-based VoIP communications.

Practical guides

Step-by-step tutorials and procedures.

Guide How to troubleshoot SIP 488 Not Acceptable Here

Compare SDP offers, codecs, and media settings when a trunk or endpoint rejects a call.

Troubleshooting

Related failures, errors and diagnostics.

Troubleshooting 3CX: audio in one direction

The call is established but one interlocutor does not hear the other. SIP signaling works while, a RTP feed does not return correctly.

View → Troubleshooting A carrier trunk returns SIP 503 Service Unavailable

The remote SIP server temporarily refuses to process calls.

View → Error code 503 — SIP service unavailable

The SIP server or trunk is temporarily unable to process the request.

View → Error code 487 — SIP request terminated

The SIP transaction was canceled, often after a CANCEL request.

View → Error code 408 — SIP request timeout

The SIP request did not receive a final response within the expected time.

View → Troubleshooting Calls fail with SIP 488 Not Acceptable Here

The destination rejects the media offer or selected SDP parameters.

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