An exchange data link helps you overcome some of the problems associated with channel associated signaling protocols, by exploiting the host access control links that many switches provide.
An exchange data link passes telephony event information and traffic statistics to a computer, and can also allow the computer some control over the switch. This is commonly known as computer-telephony integration (CTI). If your switch supports CTI, you can use a Blueworx Voice Response exchange data link to provide the signaling functions that are not provided by the channel associated signaling protocol. For example:
- The telephone number that the caller dialed
could be sent from the switch
to Blueworx Voice Response,
where it can be used either to choose the application to answer
the call, or to locate the mailbox in which voice messages are left.
For this reason, an exchange data link (or another method of getting the called number) is essential when using a Blueworx Voice Response voice mail application.
- The telephone number from which the call was forwarded could be sent from the switch to Blueworx Voice Response.
- Blueworx Voice Response could send a message waiting indicator to the switch, to signal that the message waiting lamp should be turned on or off (or a stutter tone introduced) on the called party's telephone. The switch can send a response if it is unable to process the message waiting indicator.
The following types of exchange data link are provided with Blueworx Voice Response and require no additional programming:
- Simplified Message Service Interface (SMSI): for use with the Avaya Technologies central office switch
- Simplified Message Desk Interface (SMDI): for use with the Northern Telecom DMS100 central office switch
- Voice Message Service (VMS): for use with the Ericsson MD110 PABX
- Application Connectivity Link (ACL): for use with the Siemens Hicom 300 PABX
To take advantage of the exchange data link, the pSeries computer must be connected directly to the switch (as shown in Figure 1). The physical link is an EIA RS232C (V.24) serial connection:
- For an SMSI/SMDI/VMS connection, you can use a conventional null modem cable to connect one of the pSeries computer's serial ports directly to the appropriate I/O port on the switch. Alternatively, if the length or routing of the null modem cable is likely to cause problems, you can use a pair of modems to link the two ports.
- For an ACL connection you require a standard serial cable (not a null modem cable). This cable must be connected to the serial port of an adapter that supports bisynchronous communications, such as the IBM Multiprotocol Communications Controller. Again, you can use a pair of modems instead of the serial cable.
If your switch does not use SMSI, SMDI, VMS, or ACL, you can use CallPath Server to get called and calling number information, and to support call transfer and message waiting. Alternatively, if your switch has a host access control link, you can write your own signaling process to interface with it, to provide functions such as call transfer, message waiting, and call monitoring (see How voice applications access other resources).