Customer Service and Booking Hotline: +44 (0) 845 672 0175



Call Progress

An ISUP (ISDN User Part) signalling message sent in either direction during the active or set-up phase of the call, indicating that an event of significance has occurred eg. ringing, call forwarded.

Bookmark this glossary item

Share this item using the following sites:

Courses by category...

Glossary Search

Newsletter Sign-up

Our RSS Feeds...