Grandstream Networks UCM6510 User Manual page 270

4. Enable or disable "Require Confirmation" option. If enabled, the confirmation of the invited monitor's
extension is required before the active call can be monitored. This option can be used to avoid adding
participant who has auto-answer configured or call forwarded to voicemail.
5. Click on "Add". An INVITE will be sent to the monitor's extension. The monitor can answer the call and
start monitoring. If "Require Confirmation" is enabled, the user will be asked to confirm to monitor the
call.
Another way to monitor active calls is to dial the corresponding feature codes from an extension. Please
refer to
[Table 82: UCM6510 Feature Codes]
Firmware Version 1.0.10.39
and section for instructions.
[ENABLE SPY]
UCM6510 IP PBX User Manual Page 269 of 339