6.6.2 Two-Transformer Option. Black Box ME280C-35, ME280A-X21, ME280C-530, ME280AE-35

SHM-768K

The RM110A rack serves a number of different modems. To choose the appropriate power supply option, a summation of all the card power consumptions must be made (Table 6-1).

Table 6-1. Power Consumption per Card.

Card Name Power

Consumption

Per Unit

Required

P.S. Option

ME280C-530 9 VA (100 VA—10 Cards)

(200 VA—14 Cards)

ME280C-35 7 VA (100 VA-14 Cards)

6.6.2 T

WO

-T

RANSFORMER

O

PTION

This option provides dual, redundant 100 VA transformers in a single powersupply module. The PS-1/PS-2 switch selects the power-line transformer to be used. In the event of a failure of one transformer, it is possible to switch over to the second transformer. The LEDs indicate which of the two transformers is being used (Figure 6-2).

39

SHM-768K

1

9

GND

RCV

XMIT

7 8

Figure 6-2. Rack Enclosure with Dual Power Supply.

The item numbers in Table 6-2 correspond to the reference numbers in Figure 6-2.

4 5 6

PS-1 PS-2

Power

2 3

40

3

4

7

8

Item

1

2

5

6

9

SHM-768K

Table 6-2. Controls, Indicators, and Connectors.

Control, Indicator or Connector Function

Card Slots Slots for installation of SHM-768K cards

(slot no. 1 located at the left-hand side).

Unused slots are closed with blank panels.

Power Supply Module

POWER Switch

PS-1 Indicator (DT power supply only)

PS-1/PS-2 Selector

(DT power supply only)

Provides power to modules installed in the enclosure.

Turns the power supply ON/OFF.

Lights when Power Supply 1 (PS-1) is operating

Selects the active power supply.

PS-2 Indicator

(DT power supply only)

Power Connector

Lights when Power Supply 2 (PS-2) is operating.

Power connector with integral fuse.

Main Channel Connectors (J1) DB25 connectors for the module DTE connection. For pinouts of available interfaces, see Table 3-1. Alternatively, use an interface adapter.

4-Wire Terminal Blocks (TB1) For connection of 4-wire lines. Each modem card has a separate terminalblock connector.

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