Grandstream Networks UCM6510 User Manual page 342

Outbound Prepend
Delay Before Callback
Destination
Configure the prepend digits to be added at before dialing the outside
number. The number with prepended digits will be used to match the
outbound route. '-' is the connection character which will be ignored.
Configure the number of seconds to be delayed before calling back the
user.
Configure the destination which the callback will direct the caller to. Two
destinations are available:

IVR

DISA
The caller can then enter the desired number to dial out via UCM6510.
UCM6510 IP PBX User Manual
Version 1.0.20.31
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