Ac/Dc/Dc Redundant Power; Power Connection; Power Disconnection; Connecting The Ac Power Cord - Transition Networks SM24DP4XA Quick Start Manual

SM24DP4XA Quick Start Guide

AC/DC/DC Redundant Power

The three power inputs (AC/DC/DC) are redundant but in active/standby mode. There is failover between the
three inputs but selecting primary and secondary is not supported. To select the primary and secondary inputs:
1. Between AC and DC : Both AC and DC will convert the input power to 12VDC output to the PCB; the design will
compare the voltage of 12VDC output and select the higher voltage as the primary power. If the primary power
fails, the secondary will take over.
2. Between two DC inputs: The DC input with higher voltage is the primary input, the other is the secondary
input.
Selecting the priority between AC and DC is not supported, but you can select between two DC inputs by
adjusting the DC output. See the Install Guide.
Power Connection: Warning: Connect the power supply to the switch first, and then connect the power supply to
power. Otherwise catastrophic product failure may occur.
1. Verify that power is off to the DC circuit that you are going to attach to the switch PoE DC-input connector.
This can be either of the two power supplies (AC-input or DC-input) or site source DC.
2. As an added precaution, place an appropriate safety flag and lockout device at the source power circuit
breaker, or place a piece of adhesive tape over the circuit breaker handle to prevent accidental power restoration
while you are working on the circuit.
Power Disconnection: To disconnect power from the switch after a successfully boot: 1. Turn off power to the
switch. 2. Disconnect the cables.

Connecting the AC Power Cord

You can order one AC Power cord as a separate option. 1. Connect the AC power cord to the AC power receptacle
of switch. 2. Connect the other end of the AC power cord to the AC power outlet. 3. Check the SYS LED. If it is lit,
the power connection is correct.

Connecting the DC Input(s)

Two DC Power Supply options are available (ordered separately): 25131 for 48VDC and
25079 for 24VDC, 76.8Watts. See the Install Guide for details. The SM24DP4XA DC
input is dual +24/+48 VDC or -24V/-48V VDC. 1. Insert the negative/positive DC wires
into the + and - terminals, respectively. 2. To keep the DC wires from pulling loose,
use a small flat-blade screwdriver to tighten the wire-clamp screws on the front of the
terminal block connector. 3. Check the SYS LED. If it is ON, the power connection is
correct.

Initial Switch Configuration via CLI

1. Use an RJ-45 cable to connect a terminal or PC/terminal emulator to the switch
port to access the CLI. 2. Attach the RJ-45 serial port on the switch front panel to
the cable for Telnet/CLI configuration. 3. Attach the other end of the DB-9 cable to
a PC running Telnet or a terminal emulation program such as HyperTerminal or
TeraTerm. 4. After powering up the switch for the first time, you can perform the
initial switch configuration using the CLI (Command Line Interface). For managing
other switch features, see the CLI Reference for details.
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