User`s manual

“VERIFY T” to let you know you are in the right
part of the program; press [SELECT] to begin the
Test operation. The display will show “NOTHING
IN LIST.”
After entering the Test mode, use the following
steps to send a signal from the transmitter and
evaluate whether that signal reached the CCU
with enough strength:
4.
5.
Figure A-l Installer Testing Link
1.
Refer to Figure A-l. Use a long wooden
pencil, or other non-metallic device to hold
the transmitter in place. You must keep
away from the transmitter, since your body
can affect the transmission of the radio
signals.
2.
Use another long wooden pencil to press
the transmitter button.
3.
The Display Control keypad should sound
three beeps to indicate that the signal
reception is considered good enough for
reliable communications. If the keypad
sounds only two beeps, the signal was
received, but reception is not good
enough; you must take steps to improve
the reception. If there is no beep at all, the
signal was not recognized at the CCU
at all.
A two-beep or no-beep response can
indicate either: 1) electronic noise is so
strong that the signal cannot overcome it,
or 2) something on the premises is block-
ing the signal.
When the signal seems to be marginal, the
first and easiest step is to move the
transmitter slightly (6 inches may be
enough). If many sensor positions fail the
check, moving the CCU’s antenna may
help.
The following section “Reception Factors,” dis-
cusses reception factors in some depth and may
be of some help.
Check communication for every proposed trans-
mitter location, with both the sensor and the CCU
positioned as exactly as possible.
Reception Factors
Two major factors affecting clear communication
are electronic noise and the presence of large
amounts of metal.
“Noise” cannot usually be overcome, but may be
avoided if the source is local. Electrical and
telephone wiring may carry electronic noise, and
digital equipment and motors may generate the
noise. If either the transmitter or the receiver
(CCU) antenna is close to wiring, the noise from
that wiring can overwhelm the signal just as crowd
noise at a sporting event can drown out the
announcer. However, you have one advantage in
this contest against noise: if you double the
distance from the noise (e.g., from 4” to 8” away,
or 1 foot to 2 feet) you decrease the effect by 4
times. This proves how important even a small
move might be. Typical sources of noise are:
n Computers and Computer Devices
. Premises Power (AC) Wiring
. Neon Lights
A-2 AT&T Security System 8300 Installer’s Manual