User guide

Chapter 16: Setting Up IP Extensions
MAXCS ACC 6.7.1 Administration Manual 209
• SIP Extension Channel—Establishes a logical channel relationship with other an-
alog and MobileExt ports (displayed on the SIPSP board configuration, Channel Map-
ping List).
• SIP Extension Channel Activation—Associates an extension with a SIP Extension
channel when IP phones register to the system (displayed in the Extension View
window).
• Media Channel—an RTP channel connects system-to-phone, or phone-to-phone,
system-to-system to carry the digitized voice stream. The codec resource on the
VoIP board will be allocated dynamically based on connection types. If both end de-
vices are IP phones, the media channel can be connected from IP phone to IP phone
using the IP phone’s codec, except when the following is true:
• H.323 tie-trunk is used
• SIP trunk is used
• codecs at two end devices are mismatched
• extension has Agent setting checked
• voice recording is enabled at the IP extension
• a NAT router exists between AltiServ and remote IP phone
SIP supports a direct connection of the voice stream between SIP phones. H.323 tie-
trunks still require the voice stream to connect to the server.