User's Manual

ADCP-75-130 • Issue 3C • August 2006

Page 11

mounted in either a 19-inch or 23-inch EIA or WECO equipment rack. When rack-mounted,

the front panel of the DEU is flush with the front of the rack and the cable management tray

extends 3.9 inches (99 mm) beyond the front panel. For wall-mount applications, a pair of

holes is provided in the cable management tray which allow the DEU to be mounted on any

flat vertical surface. The DEU should be oriented with the front panel facing upward when

wall-mounted. Fasteners are provided for rack-mount applications.

2.3.3 Fault Detection

The DEU detects internal circuitry faults or loss of system inputs. Various front panel Light

Emitting Diode (LED) indicators turn from green to red or yellow when a fault is detected or

when an optical input is lost. The DEU transports the fault information to the DHU or

supporting DEU over the reverse path optical fiber. A corresponding port LED at the DHU or

DEU turns from green to red when the DEU reports a fault.

2.3.4 Optical and Electrical Connections

The optical and electrical connections with the DRU’s and DEU’s are supported by six optical

and six electrical ports. Each optical and electrical port consists of a status LED, an RJ-45 DC

power jack, a port enable/disable switch, and a small form factor LC type optical transceiver

(available separately). Each transceiver is color-coded to identify whether it supports single-

mode (blue) or multi-mode (black/beige) fiber. An optical port may be connected to a DRU, a

DEU, or not used. An electrical port may be connected to a DRU or not used. Unused ports are

disabled via the corresponding port enable/disable switch. When disabled, the port LED is off,

the alarm reporting function is disabled, the laser is off, and the DC power is off. Enabling the

enable/disable switch activates all functions. The DEU also provides one optical port (designated

as the host port ) for the optical interface with the DHU or a supporting DEU. The modular

optical transceivers are available as accessory items and are field replaceable.

2.3.5 Powering

The DEU is powered by 120–240 VAC (50/60 Hz) power which is supplied though a standard

three-conductor 120 VAC power cord. The power cord is provided with the DEU and is 98

inches (2.5 meters) long. A resetable circuit breaker/On-Off switch is provided at the unit

front panel. The switch applies power to the DEU internal power supply.

2.3.6 Cooling

Continuous air flow for cooling is provided by dual fans mounted on the right side of the sheet

metal housing. A minimum of 3 inches (76 mm) of clearance space must be provided on both

the left and right sides of the DEU for air intake and exhaust. An alarm is provided that

indicates if a high temperature condition (>50º C/122º F) occurs. The fans may be field-

replaced if either unit fails.

2.3.7 User Interface

The DEU user interface consists of the various connectors, switches, and LEDs that are

provided on the DEU front panel. The DEU user interface points are described in Table 3 and

indicated in Figure 7.