Cisco Systems AS5850 manual Circuit Description

Chapter 1 Cisco AS5850 Product Overview

Field-Replaceable Units

Table 1-12 DC-input Power Supply Circuits

Circuit	Description
Circuit breaker	PEMF output is enabled when this pin is shorted to the —51V
	monitor pin by way of the backplane. If the connection is broken,
	the breaker is tripped and cannot be reset until the PEMF is
	reinstalled.
Reverse polarity	An electronic interlock that provides reverse polarity protection.
Current monitor	Analog output voltage is proportional to DC-output current from
	the PEMF to the backplane, as follows: 1A of current is
	equivalent to 100 mV at the current monitor pin.
Voltage monitor	Analog output voltage is proportional to DC-output current from
	the PEMF to the backplane, as follows: 1A of current is
	equivalent to 100 mV at the voltage monitor pin.
Bell alarm	A terminal block for connecting to central office alarms (C, NC,
	NO).

Note Connect the alarm port only to a safety extra-low voltage (SELV) source using 22 AWG, or thicker, copper wire. SELV ratings are maximum 30 Volts AC (RMS), maximum 60 Volts DC, and maximum

50 VA power. The alarm port is rated for 2.0 Amp maximum current.

•Bell alarm signaling

The PEMFs provide relay outputs for standard central office bell alarms. These bell alarm contacts are available on a terminal plug mounted on the PEMF front panel.

•Online insertion and removal (OIR)

The PEMFs support OIR, which means that you can remove or replace a PEMF while the system is operating; system operation is not affected. Only qualified personnel should OIR a PEMF.

•DC-input power filtering and power distribution

The PEMF first receives –48 VDC power using analog isolation circuits. The DC power passes through a broadband EMI filter, then passes to a DC-to-DC converter on the RSC, where it is converted and then routed back to the backplane for distribution to the other cards. A single PEMF supports a fully configured chassis.

•Maintenance monitoring

The PEMF contains the environmental maintenance bus (Mbus) module with a logic card, which carries monitor signals throughout the chassis by way of two 10-pin molex MiniFit connectors.

There are no connectors accessible from the front of the PEMF; however, a DB-9 connector at the base of the PEMF (visible only from below the chassis) connects a monitor cable to an optional AC-input power shelf.

The PEMFs are located on the rear of the universal gateway. Figure 1-2shows the location of the PEMFs as viewed from the rear of the chassis.

	Cisco AS5850 Universal Gateway Hardware Installation Guide
78-10573-06 0A		1-25