WaveWare SPS-5 v9E User Manual

Page 47

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Tone/Vibe Only Example:

PagerID<CR><CR>

Multiple Message Example:

PagerID1<CR>Message1<CR>PagerID2<CR>Message2<CR>

Forced Resynchronization Example:

<DEL><DEL><DEL>PagerID<CR>Message<CR>

Multiple Messages using Forced Resynchronization Example:

<DEL><DEL><DEL>PagerID<CR>Message 1<CR><DEL><DEL><DEL>PagerID<CR>Message 2<CR>

Function Code Control Example using Function Code B:

PagerIDB<CR>Message<CR>

When incoming data is detected on the serial port, one of three things will happen:

1)

The data in the serial port input buffer contains properly formatted COMP2 command strings.

2)

A time period of approximately 10 seconds elapses after receipt of the last character on the serial port.

3)

256 characters or more accumulate in the serial port input buffer. The serial port data is analyzed character by

character to see if a properly formatted command string exists. If the serial port data contains one or more properly
formatted COMP2 command strings, then the paging message(s) will be transmitted to the specified Pager ID(s) as long
as those Pager ID(s) exist in the WaveWare v

9

Paging Encoder’s Pager Database. If a Pager ID doesn't exist in the

pager database, an error message will be output in verbose mode by the paging encoder as follows:

Invalid character in pager ID<CR><CR><RS><CR>

Any portions of the serial port input buffer that don't meet the COMP2 message formatting requirements are discarded.
The original COMP2 Protocol has an inherent weakness of using the <CR> character to delimit both the Pager ID Field
and the Message Field. This approach allows the possibility of an extra or missing <CR> character to cause the host
system and the paging system to get out of synch with each other, causing multiple paging messages to be rejected by
the paging system. A more robust version of the COMP2 protocol uses Three <DEL> characters as indicators of the
beginning of a COMP2 command string. The use of three <DEL> characters at the beginning of each output message
assures that out-of-synch conditions will not occur. The forced resynchronization method is optional. As additional
synchronization insurance, the WaveWare COMP2 implementation has been designed to stay in synch even if one or
more <CR> characters immediately precede a properly formatted COMP2 command string.

If the 10 Second Timeout occurs while waiting for all of the characters required for a properly formatted COMP2
message to arrive on the serial port, the data in the serial port input buffer will be discarded. If 256 or more characters
arrive in the paging encoder’s serial port input buffer, and the first 256 characters contain all of the elements of a properly
formatted COMP2 Command String except for the trailing <CR> character, then the <CR> will be assumed and only the
first 256 characters of the input buffer will be processed as a valid COMP2 paging message.

If the serial port input buffer becomes filled with greater than 600 characters, the paging encoder will output either a
hardware or software flow control response, depending upon how the system is configured. Once the serial port input
buffer drops below 450 characters, the paging encoder will use flow control signals to indicate that it is no longer busy and
that additional data can be delivered to the serial port.

This Completes the “COMP2 Interface Specifications”

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