Specifications

Appendix J – Contact Monitoring Function - 23
Appendix J – Contact Monitoring Function
The Contact Monitoring Function is designed to allow the SPS-5 Paging System to be used for purposes of
automatically transmitting predefined messages upon contact closure and/or contact open conditions. The Contact
Monitoring Function can be activated during the process of programming the pager database using the WaveWare
Paging Encoder Setup software. The Contact Monitoring Function is available only with the TAP mode of operation.
An alarm pushbutton option is available on the SPS-5 paging system, which allows you to press a momentary
pushbutton on the front of the SPS-5 enclosure to perform alert paging in addition to performing TAP protocol serial
port interface operations. The Contact Monitoring Function operates as follows:
Concurrent with the paging encoder monitoring the serial port for normal TAP messages, the Contact Monitoring
Function monitors the RTS serial port signal on the paging encoder serial port for voltage changes. A contact
closure event occurs when the RTS line swings to a negative voltage, and a contact open event occurs when the
RTS line swings to a positive or zero voltage. The RTS line on the paging encoder 9 pin serial port connector is Pin 7.
When programming the SPS-5 Paging System pager database, each of the six sequentially defined groups of pagers
in the pager database can be associated with the Contact Monitoring Function and one of two configurable
predefined messages of up to 14 characters each. If a pager group has the Contact Monitoring Function active, all
pagers in that pager group will receive a predefined message.
Some practical applications of the Contact Monitoring Function are as follows:
• In mission critical environments, the Contact Monitoring Function can be used to monitor the host system and
notify someone's pager that the host system needs attention. To accomplish this, wire up Pin 7 of the paging
encoder's 9 pin serial port to a serial port pin on the host system. The host system serial port pin must change
voltage when the host system is powered up or active. If the host system gets disconnected from the paging
system or the host system loses power or stops functioning, the Contact Monitoring Function will come into
play.
• Use a mechanical switch or other form of contact closure or contact opening to cause paging to occur. To
accomplish this, wire up Pin 7 of the paging encoder's 9 pin serial port to one side of the switch, and wire Pin 8
(CTS) of the paging encoder's 9 pin serial port to the other side of the switch. Upon closure or opening, the
voltage provided by the CTS signal on the paging encoder's serial port will provide the signal necessary to
trigger the Contact Monitoring Function's paging output.