User Manual

ADCP-75-179 • Preliminary Issue A • September 2004 • Section 2: Description
Page 2-5
© 2004, ADC Telecommunications, Inc.
2.5 RF Signal Level Adjustments
The HU is equipped with several attenuators for adjusting the signal levels of the forward and
reverse path RF signals. The attenuators provide an attenuation adjustment range of 0 to 31 dB
and can be set in 1 dB increments. The attenuators are software controlled and are adjusted
through the EMS software GUI, NOC/NEM interface, or SNMP interface.
The host forward path attenuators adjust the level of the two input RF signals to the HU.
Using the forward path attenuator, an input signal with a nominal composite signal level of –12
dBm to –43 dBm can be adjusted to produce maximum power output. Additional external
attenuation is required if the input signal level is greater than –12 dBm.
The host reverse path attenuators adjust the level of the two output RF signals from the HU
and will add from –1 dB of gain (attenuator set to 31 dB) to +30 dB of gain (attenuator set to 0
dB) to the two RF output signals at the HU.
2.6 Propagation Delay
The HU forward and reverse path propagation delays may be adjusted in 0.1 µsec increments
within a range of 0 to 63 µs. The propagation delay is software controlled and may be adjusted
through the EMS software GUI, NOC/NEM interface, or SNMP interface.
2.7 Optical Connection
Optical connections between the HU and the RU (STM) are supported through two SC-type
optical connector ports. One port is used for the forward path optical signal connection and the
other port is used for the reverse path optical signal connection.
2.8 Controller Area Network Interface Connection
Controller Area Network (CAN) interface connections between multiple HUs are supported by
a pair of RJ-45 jacks. One of the jacks is designated as the network IN port and the other jack is
designated as the network OUT port. The CAN interface allows up to 24 HUs to be connected
together (in daisy-chain fashion) and controlled through a single EMS computer.
2.9 Service Interface Connection
The service interface connection between the HU and the EMS computer is supported by a
single DB-9 female connector. The service connector provides an RS-232 DTE interface. When
multiple HUs are networked together, the supporting EMS computer may be connected to the
service connector of any one of the networked HUs.
2.10 Auxiliary Interface Connector
An auxiliary communication link is provided between the HU and the STM for customer use.
The auxiliary interface is supported by a single DB-9 female connector. The auxiliary connector
provides an RS-232 DTE interface. The auxiliary communications link can be used to remotely
monitor and control other network equipment that may be located at the remote unit site such as
the antenna.