 amount of work formerly needed to integrate these capabilities when they were separate systems, there is still considerable com- plexity in integrating the telephone system with a computer database for applications such as Screen Pops or Unified Messaging. As with all technology purchases, organizations wanting to roll out Computer Telephony applications must consider their systems and procedures already in place and the costs and trade- offs of different options. 160 to The Telecom Handbook CHAPTER 7 SCREEN POPS One of the more commonly used Computer Telephony Inte- gration applications is found in some Incoming Call Centers and known as a Screen Pop. A Screen Pop is the delivery of a com- puter screen displaying information about the caller that arrives at the desktop at the same time as the telephone call. When some- one calls you, the telephone system recognizes the caller either by the Caller ID (the number from which they are calling) or by asking the caller to enter an identifying account number when the call is answered. For example, "Thank you for calling Comware Systems, Inc. For immediate hotline support enter your 5 digit customer identification number." Once the caller is iden- tified, the telephone system sends a message to the server on the local area network identifying the caller and providing instruc- tions on what customer information to deliver to which desktop. Computer Telephony Applications Development Telephone Call Control The starting point for developing Computer Telephony ap- plications is a set of basic services including (1) call control, (2) call monitoring and (3) system feature activation. Computer Te- lephony includes software that communicates with the telephone system, telling it what to do. This application can access a set of commands such as "Make Call", "Answer Call" and "Transfer Call". When a command is issued by the Computer Telephony software, the telephone system attempts to complete the assigned task and reports back to the application with the result. The re- sult m