What does Windows error code 7013 (ERROR_CTX_MODEM_RESPONSE_NO_CARRIER) mean?

ERROR_CTX_MODEM_RESPONSE_NO_CARRIER

Carrier detect has failed or carrier has been dropped due to disconnect.

ERROR_CTX_MODEM_RESPONSE_NO_CARRIER is Win32 error 7013 (0x00001B65) and concerns carrier establishment or retention during a legacy Remote Desktop callback.

What to verify

Verify whether the modem detects and retains carrier for the remote callback connection. Check dialed number and call timestamps, modem result codes, and line and carrier-detect status.

Likely causes

• the remote side did not answer with a compatible modem.
• line quality caused carrier loss.
• the call was disconnected after negotiation.
• modem standards or speeds are incompatible.

Troubleshooting steps

1. Collect dialed number and call timestamps.
2. Record modem result codes.
3. Correlate line and carrier-detect status with TerminalServices operational logs, session and user-configuration records, device or modem diagnostics, and the caller’s connection trace.

Handling, retry, and recovery

Verify the remote endpoint and line, lower negotiation settings when appropriate, and retry only after a test call can sustain carrier.

Related errors

ERROR_CTX_MODEM_RESPONSE_NO_DIALTONE fails before dialing; this code occurs after dialing or negotiation begins

Example

A callback reaches the remote number but carrier drops during negotiation. Testing both modems at a common speed isolates an incompatible configuration.

References

• Microsoft: Win32 system error range containing this code
• Microsoft: Remote Desktop Services API
• Microsoft: WTS configuration classes
• Microsoft: WTSAPI32 reference