4x2 (3x2) Format
Another popular means of reporting events is known as
the
4x2
(or
3x2
Format), often used as an alternative to
the
Standard
and the
Expanded Formats,
which were
previously discussed. As its name implies, it provides a 4-
(or 3-) digit
Account Number,
followed by a 2-digit
Report
Code
. In this regard, it is similar to the
4x1
(or
3x1
)
Expanded Format (see pages B-12 through B-14), except
that rather than using 2 rounds to complete the message,
the entire
4x2
(or
3x2
) transmission is accomplished in a
single round. Excluding
hexadecimal
"A," which is
typically not processed, the CP-220A will accept up to 225
2-digit
Alarm Codes
(15 possibilities for each of the two
Report Code
characters), which should be more than ample
for all but the largest installations. The table at the upper
right suggests how most of these 225
Alarm Codes
might
be used in a conventional installation.
However, since many installations do not follow this
pattern, let's use an example of a control panel protecting
a commercial premises using 100 zones – not unusual
when you consider that today's technology allows multiple
(and separately annuciated) detectors to occupy the same
wire run (or wireless channel). Of these 100 zones, suppose
75 are used for
burglary/panic
functions and the
remaining 25, for
fire
. The table at the right shows how
each of the
4x2
Reporting Codes can be uniquely
programmed to report each
alarm
by
zone
– and
restorals
by
group
– to the Central Station.
Virtually any programming scheme is possible when used
with the
4x2
or
(3x2)
Reporting Format, as long as it's
recognized by the Central Station. An
Automation System,
if used, can easily sort out these assignments, and
provides a meaningful message for the operator.
Page B-20 Appendix B:
CP-220A Central Station Receiver
Communication Formats
Hook-Up and Installation Manual