Motorola SG 2000 用户手册
5 - 2 8 O p e r a t i o n
SG 20 00 Ins tal la tion and O pera tion M anua l
Desc ription
Functio n
Alarm test point
(
ALRM TP
) provides access for measuring the cross-over optical level
threshold.
3 dB test point
(3 dB
TP
) is used to measure the optical power of the primary receiver.
Measurements at this test point are 3 dB less than the actual value.
Potentiometers ICS1
through ICS4
Control the attenuation of the ingress control switches (ICS) when they are
installed in the return paths of the RF output ports. The factory setting is for
minimum attenuation, however, they can be set for a maximum attenuation
of approximately 40 dB. The following list indicates the potentiometer and
its corresponding housing port:
installed in the return paths of the RF output ports. The factory setting is for
minimum attenuation, however, they can be set for a maximum attenuation
of approximately 40 dB. The following list indicates the potentiometer and
its corresponding housing port:
ICS1
housing
port
IN
RF chassis port 1
ICS2
housing port
OUT
RF chassis port 2
ICS3
housing port 1
RF chassis port 3
ICS4
housing port 3
RF chassis port 4
Figure 5-29 illustrates the MCB board, switches, potentiometers, and test points:
F i g u r e 5 - 2 9
M C B b o a r d
M C B b o a r d
ICS4
S2
S1
ICS3
ICS2
ICS1
ALRM
3 dB TP
ALRM TP