I have a 3640 with a WIC1T serial module in the WIC slot. Is it possible to configure a chanellised T1 for voice on this interface. Or do I have to use a channelised T1 WIC. I will be connecting this interface to another 3640 with the same interface using a rolled serial cable. One router will act as a branch office voice router the other router will be an configured as an ISDN switch.