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Figure 4: DC Power Supply Connection
into an AC power source, the plug should be connected to the Telephone Modem. There are no
special tools required.
2.4.2
Installation with DC Power
DC power may be used instead of a power transformer. This requires a 2.5 mm socket, J3
(location shown in Figure 3) with the positive voltage on the center and the common on the
concentric supplying 12VDC at 1.0A as shown below (Figure 4):
2.5 INTERFACE WIRING
Table 5 and Table 6 list the interface wiring for F271XA telephone modems. The
RJ11 is used with a single line 2-wire telephone as shown in Table 5. The barrel connector (J3) is
wired in parallel with the 12-pin connector (P1) for power. When installing the telephone modem
in a standalone or dual-card rack-mount chassis, a power transformer is plugged into barrel jack
(J3). When installing the Telephone Modem in a 20-Slot rack-mount chassis (HF-20A or VMX20)
with optional power supplies (AC300WR) the 12-pin connector (P1) is used. Wiring for the 12-
pin connector is shown in Table 6. Hard Metric Type-C connector (J5) is used for backplane
communications, when the Telephone Modem is placed in a VMX20 chassis. Figure 3 identifies
the locations for the 12-pin power connector (P1), modular power jack (J3), and HM Type-C (J5)
connector.
Table 5: Telephone/Analog Wiring
Pin Number
Signal Designation
Color
1
Not Used
2
Not Used
3
Ring
Green
4
Tip
Red
5
Not Used
6
Not Used
Table 6: (P1) Chassis Power/Alarm Wiring
Pin Number
Signal Designation
1
+12 VDC
2
+12VDC
3
Signal Ground
4
Signal Ground
5
Signal Ground
6
Frame Ground (Chassis)
7
System Alarm Interface
8
Signal Ground
9
Signal Ground
10
+12 VDC
11
+12 VDC
12
+12 VDC
