Problem with Toshiba IP Phone and Cisco 3560 PoE Switch

We have had recently had a problem with a Cisco 3560 PoE switch and a Toshiba IP phone. The issue is that when a call is made from a Toshiba IP phone (problem spanned phone and phone/firmware versions), the conversion was one way. The party on the remote end could not hear the party in private banking. We have this switch deployed several other places with the same version of IOS and don’t see the issue. Finally the mystery has been solved. After running capture on the links and doing troubleshooting, I was able to determine that the "switchport voice vlan 1" command on each interface that was used for a phone was the magic bullet. For some reason, in its given setup, this switch needs this command to make everything work whereas it isn’t needed in other places. Cisco is current still looking into the issue and last I heard it is at TAC level 4.

Networking switch Cisco VoIP