User's Manual

ADCP-75-158 • Issue 1 • July 2003 • Section 2: Description

Page 2-17

instead connects to a lightning protector that is mounted on the bottom of the cabinet (see

Section 3.6). A coaxial jumper cable is provided (included with the enclosure) for connecting

the STM to the lightning protector.

5.5 RF Signal Level Adjustment

The STM is equipped with a digital attenuator for adjusting the signal level of the forward path

RF output signal. The remote forward path attenuator adjusts the level of the output RF signal

at the RU antenna port and will add from 0 to 31 dB of attenuation to the output signal level.

The attenuator can be set in 1 dB increments. The attenuator is software controlled and is

adjusted through the NOC/NEM interface or the EMS software GUI.

5.6 Optical Connection

Fiber optic connections between the STM and the HU are supported through two SC-type

optical connector ports. One port is used for connecting the forward path optical signal and the

other port is used for connecting the primary reverse path optical signal.

5.7 Service Interface Connection

The service interface connection between the STM and a local laptop computer loaded with the

EMS software is supported by a single DB-9 female connector. The service interface connector

provides an RS-232 DTE interface. The STM service interface connector supports local

communications with both the STM and the corresponding HU.

5.8 Powering

The STM is powered by 120 or 240 VAC (50 or 60 Hz) power which is supplied through a

three-conductor AC power cord. The power cord is provided with the RU outdoor cabinet or

indoor mounting shelf. The power cord connects to an AC connector mounted on the STM front

panel. A switch on the STM front panel provides AC power On/Off control.

5.9 Cooling

Continuous air-flow for cooling is provided by a single fan mounted on the rear side of the STM

housing. An alarm is provided that indicates if a high temperature condition (>50º C/122º F)

occurs. If the temperature falls below 32º F (0º C), the fan automatically shuts off. The fan may

be field replaced if it fails.

5.10 User Interface

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

provided on the STM front panel. The STM user interface points are indicated in Figure 2-8 and

described in Table 2-4.