Starting with version 4.1 of Cisco Unified CallManager Express, Cisco has introduced support for hardware based multiparty conferencing. This is a great improvement over the default software based conferencing that is also available in CallManager Express. What this means is that Call Manager Express can support up to 32 parties in a Conference call using the G.711 codec and up to 16 parties in a conference Call using the G.729a or G.729ab codecs. This is a

The below is a summary of digital voice standards from the ITU.