Once adequate bandwidth is administered and phones are in place, you've got a pretty sexy system. Top-of-the-line is the 7960 phone, which has lots of soft buttons and a 133x65 pixel display. The phone is essentially an Internet appliance, with its own onboard web server (which can do chores like send out captures of what's on the display, given appropriate security access) and a stripped-down XML-rendering browser. This browser gives the phone its interactive character. When the phone powers up, it contacts CallManager, which associates that phone with an administrator-designated initial service URL (effectively the phone's home page). Any web server on the network (or the Internet as a whole, though that's not typical) can serve this page.
A page served to a Cisco IP phone is not a typical HTML web page. It is an XML page making use of a few Cisco-defined XML objects that let developers control things like loading behaviors of soft buttons and presenting menus. The key point is that putting an app onto one of these phones is pretty straightforward to anyone who's put together a server-side web app. Setting aside some of the issues of getting an adequate IP infrastructure in place and the predictable early blunders of a new technology, it's hard not to like a system with a visual interface that can easily be tied into corporate databases and apps.
Call control on the 79XX phones is handled by Cisco's own "Skinny" protocol, though it's possible to obtain 7960s with SIP support; CallManager handles interactions using not only Skinny but H.323 and MGCP. Given Cisco's overall support for SIP (including several SIP gateways and a SIP proxy server), we could expect SIP support on CallManager soon.
For the skinny on Skinny and other AVVID issues, two books that stand out in the telephony field are from Cisco Press. Cisco CallManager Fundamentals (ISBN 1-58705-008-0) delivers exactly what it promises and Developing Cisco IP Phone Services (ISBN 1-58705-060-9) gets you thinking about what services you might create for your enterprise, complete with a CD-ROM CallManager simulator.
Article provided courtesy of Communications Convergence Magazine. Copyright © 2002 CMP Media, LLC. All rights reserved.