User Manual

DRAFT RF Front End System Integration Manual
044-05082 Rev. A
1-2
March 2001
1-2.1.3 Masthead Unit Interface
The Masthead Unit Interface (MHUI) interfaces the MHU to the host base station. It provides a
user friendly control panel for power level adjustment and display. The control panel is key
activated and displays major, critical and minor alarm conditions via LED displays. Refer to sec-
tion 2 for a more detailed description of the MHUI controls.
The enclosure houses a low power duplexer, a control board, the control panel, cell size variable
attenuators (both Rx and Tx) and a preamp. The system reports and displays alarm faults to the
external summary module via an RS-485 bus or form C dry contact relays. Refer to figure 4-4 for
the MHUI functional block diagram.
The MHU-MHUI pair operates between 1dB and 16dB of cable loss in the transmit/receive coaxial
cable. Therefore, the maximum distance between the MHU and MUI depends on the cable type
used (e.g. 7/8”, 1/2” or 1/4” foam-dielectric coaxial cable).
Note: The Connector Identification (A,B and C) is for reference only
and not necessarily labled on the actual connector
Figure 1-1 Masthead Unit Blind mate Connector Interface
Table 1-1 Blindmate Connector Pin Designation
Pin Function
1A +26 VDC
2A +12 VDC
3A -8 VDC
4A COM
5A-12A Not used
1B Not used
2B TX IN
3B TX OUT
4B Not used
1C Mute
2C-4C Not used
5C RS-485H
6C RS-485L
7C COM
8C-12C Not used
1
2
3
4
1
6
1
6
7
12 12
7
AB
C