This is from the 3.3 doc, but it talks about remote SCCP phone support limitations:
Remote skinny client control protocol (SCCP) phones connected across WAN links are subject to the following restrictions:
–Cisco TAC will not handle any voice or signaling issues for remote IP phones, unless the same issue can be replicated for LAN phones.
–E911 or emergency calls are not supported from remote IP phones.
–All calls made to and from remote IP phones must use G.711. Cisco CME does not support the ability to specify G.729 codec for remote IP phones.
–For inbound or outbound calls, remote IP phones cannot fail and go over to a PSTN connection. Remote phones must use the WAN for all calls, even if available bandwidth is not sufficient to guarantee voice quality.
–Remote IP phones do not support Network Address Translation (NAT). All Cisco CME phones must use IP addresses that are routeable to and from Cisco CME. Remote IP phones must be able to access the IP addresses that are used for all other local and remote phones.
–All PSTN access is through the central site only. PSTN termination at the remote site is not supported.
–Cisco CME does not support Call Admission Control (CAC) for remote SCCP phones, so voice quality can degrade if a WAN link is oversubscribed. High-bandwidth data applications used over a WAN can cause degradation of voice quality for remote IP phones.
http://www.cisco.com/univercd/cc/td/doc/product/voice/its/cme33/cme33sa/cme33ovr.htm#wp2247785
Mary Beth
