[Asterisk-Users] Call Waiting not detected

[Derek Beaumont]

My problem is that I cannot get call waiting to work when somebody calls
from the PSTN.
My hardware:
	X100P
	TDM400P

Working Scenario:
	Phone A, Phone B, and Phone C are all connected to my Asterisk
box

	Phone A calls Phone B
	Phone B picks up and they have a conversation
	Phone C calls Phone B
	Phone B hears a beep and is connected with Phone C

Non-Working Scenario:
	Phone A and Phone B are connected to Asterisk, Phone C is an
outside caller

	Phone A calls Phone B
	Phone B picks up and they have a conversation
	Phone C Calls Phone B (Phone B does not hear the call waiting
beep)

I do have call waiting defined in my zapata.conf:
callwaiting=yes is listed immediately under [channels] so it should
apply to all channels that I define

Any ideas why this happens?