1558A APS
2-2
Installation
2.4
Wiring & Connections
There are several wiring connections that must be performed
to install the APS unit. The following paragraphs describe
how to attach the APS unit to the associated T1 lines, power
connections, alarm connections, and COM BUS connec-
tions.
Figure 2-1
should be used as a reference for the fol-
lowing paragraphs concerning installation of the 1558A
APS unit.
2.4.1
Chassis Ground Connection
The 1558A unit should be connected to a good earth ground.
To connect ground to the unit, attach a 26 gauge or larger
wire from the rear panel screw terminal labeled ‘GND’ to a
good earth ground.
Caution: Voltages in excess of 100 VDC may
be present on the T1 telecommunications lines. Before
connecting the APS unit to telecommunication lines,
insure that the rear panel screw terminal labeled ‘GND’
has been connected to a good earth ground.
2.4.2
DC Power Connections
The rear panel screw terminal labeled ‘-DC’ and ‘RTN’ are
used to connect -20 to -56 VDC to the 1558A. The 1558A
may be wired with redundant power inputs by wiring an
external source to both the PWR A and PWR B -DC/RTN
terminals. To connect power to the APS unit, perform the
following.
PWR A Wiring: Connect an external power source (-20 to
56 VDC) to the rear panel screw terminal labeled PWR A
‘DC’ and ‘RTN’. If using the provided AC to DC wall
power transformer, connect the RED wire to the ‘RTN’ ter-
minal, the BLACK wire to the ‘-DC’ terminal and the
GREEN wire to the ‘GND’ terminal.
PWR B Wiring: Connect an external power source (-20 to
56 VDC) to the rear panel screw terminal labeled PWR B
‘DC’ and ‘RTN’. If using the provided AC to DC wall
power transformer, connect the RED wire to the ‘RTN’ ter-
minal, the BLACK wire to the ‘-DC’ terminal and the
GREEN wire to the ‘GND’ terminal.
2.4.3
Alarm Connections
The 1558A has alarm contacts provided at the rear panel
screw terminals labeled ‘COMMON’, ‘NC’, and ‘NO’. The
alarm relay is operated when power is present to the 1558A.
To connect the APS alarm relay to an external customer
alarm surveillance system, perform the following:
• Connect a 26 gauge wire to the rear panel screw terminal
labeled ‘COMMON’ to the external alarm system.
• Connect a 26 gauge wire to the rear panel screw terminal
labeled ‘ALARM NO’ (normally open) or to ‘ALARM
NC (normally closed) to the external alarm system. Note
that the alarm relay is normally operated when power is
connected to the unit.
2.4.4
T1 Connections
All T1 lines are connected to the APS unit using modular 8-
pin RJ48 cables (three 10' cables come with the unit). Insert
the RJ 48 connectors into the rear panel receptacles labeled
NET A, NET B, and DTE. Connect the other ends of the
cable to the appropriate T1 A and B facility equipment and
to the DTE equipment. The DTE port is not designed for
direct connection to a TELCO T1 facility. The modular pin
outs and their functions are shown in the following table.
!
Pin
NET A & B, RJ48
DTE RJ48
1
Data In, Tip
Data Out, Tip
2
Data In, Ring
Data Out, Ring
3
Not
Used Not
Used
4
Data Out, Tip
Data In, Tip
5
Data Out, Ring
Data In, Ring
6
Not
Used Not
Used
7
Not
Used Not
Used
-20 to -56 VDC, 200 MA
S1
DTE
COM BUS
NET B
NET A
IN
OUT
GND
–
V
DC (
A
)
RT
N
(
A
)
–
V
DC (
B
)
RT
N
(
B
)
Alarm
NO
C
o
mmo
n
Alarm
NC
S2
S3
S4
Figure 2-1
1558A Rear View
