Core Issue
The VG224 is configured to have call transfer, conference call, and call waiting features. These features work fine except on one instance.
If a call comes in on a primary line and a second call also comes in, the user can change between calls by using the hook-flash button. However, the user can no longer transfer either of the two calls to a third line.
Resolution
This is a feature limitation.
When VG224 is configured as an SCCP analog device, it is a single line phone with the call waiting feature.
Once a second call comes in, transfer is not possible. Since this is an analog single line phone, the only type of signal it can send other than dual tone multifrequency (DTMF) is a hook-flash. This hook-flash is used for many features, such as transfer, call waiting, conference, and so forth, must be used independently, and cannot be used simultaneously.
When you build each extension as a phone in Cisco CallManager, it is built as a single line phone with a call waiting channel. When you receive an incoming call in call waiting, you use up the second channel. Because both call waiting and transfer require flash-hook, you cannot do the transfer if the second channel is busy.
Voice Gateways
VG248 Analog Phone Gateway
VG224 Gateway
