Operating instructions

LOCAL OPERATION
3-85
POCSAG
Overview
The POCSAG system is an international standard for radio pager operation. The system operates
by broadcasting digital messages on a common frequency, only alerting the addressed radio pager
when the transmitted address matches that of the pager. The signal transmitted consists of two
main elements, the address and the message.
The POCSAG test facility within the Service Monitor generates a paging signal containing all
elements of a ‘live’ signal. This signal is transmitted using the RF generator output to feed a
suitable test rig or TEM cell.
The decoder test facility allows a POCSAG type encoded signal to be decoded and displayed.
To access the POCSAG test facility use the following key sequence:-
[Rx TEST], [Tones], [POCSAG].
The screen and menu shown in Fig. 3-28, POCSAG radio pager test screen and menu, will be
displayed.
B2605
Fig. 3-28 POCSAG radio pager test screen and menu
The facilities offered by this Service Monitor for testing radio pagers are:-
• The RF generator of the Service Monitor can be set to any frequency within the specified
range of the Service Monitor. The default frequency is 153.125 MHz.
• The RF level can be set to any level within the normal operating level of the Service Monitor.
• The modulation level of the signal can be to any level within the normal operating level of the
Service Monitor. The default level is 1.5 kHz.
• The
Address and Alert warning type can be set to any of the four available. The alert message
generated by radio pagers can be selected from four formats. The selection is controlled by
two function bits within the transmitted address codeword. The Service Monitor displays a
representation of the audible alert message, shows the relevant function bit combination, and
describes the type of message that is transmitted after the particular alert message. See Fig. 3-
29, Alternative address/warning messages.
The Service Monitor has 7 different inbuilt messages which can be sent to the radio pager. These
messages are selected by repeated presses of the [Select Message] key. The selected message is
shown in a panel on the display with the legend Mess 1 (or
Mess 2 etc.).
The bit rate of the transmitted test signal can be set by the user within the limits 400 Hz to
4.8 kHz. The default bit rate is the standard system bit rate of 512 Hz.
The generated data can be transmitted with normal or inverted polarity.