Which two characteristics apply to a CAS T1 interface?（）

A.SIP support in dial peers is a Cisco IOS function. 
B.Use the notify-based DTMF relay mechanism that is proprietary to Cisco.
C.SIP support in Cisco IOS is a function of localized call processing integrated with Cisco Unity Express. 
D.Use either the notify-based DTMF relay mechanism that is proprietary to Cisco or the RFC-based DTMF relay. 
E.The SIP server must be configured for the E.164 numbers that are going to register with the Cisco CallManager Express database.  

A.Echo is the discernable leak-through of your own Rx path into your own Tx path. 
B.Echo is the discernable leak-through of the packets of your Rx path into your own Tx path. 
C.Echo is the nonaudible leak-through of the packets of your Rx path into your own Tx path. 
D.Echo is the audible leak-through of the packets from the transmit path into your own receive path. 
E.Echo is the nonaudible leak-through of the packets of your Tx path into your own Rx path.

A.The gain functionality applies to outbound audio packets. Distortion is created when an external participant causes echo. 
B.The distortion is unrelated to the gain functionality. Rather, it is a result of the company trying to maintain too many conference calls at one time. 
C.This functionality cannot discriminate between a local VoIP source that requires volume gain and a CO-powered PSTN source that does not require volume gain. 
D.This functionality cannot discriminate between a remote VoIP or Foreign Exchange Office source that requires volume gain, and a remote VoIP or IP phone that does not require volume gain.