Page 47 of 59
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>
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
8
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”
