User's Manual

044-05156 Rev C 32
4.6.5.2 RS-485 Connectors (J4, J5)
RS-485 signals are monitored through the RS-485 9-pin female D-sub connector on the rear of the subrack.
DB9 Connector
RS-485 and Preamp Connector Definition
PIN Description PIN Description
1 RS-485 TX data + 6 No Connection
2 RS-485 TX data - 7 No Connection
3 RS-485 RX data + 8 No Connection
4 RS-485 RX data - 9 Ground
5 Ground/Shield
4.6.5.3 Preamp Connector (J6; not used)
Alarm information from the system preamplifiers are monitored through this female 9-pin sub connector located on
the rear of the MCPA subrack. The OPAF-1923-P07C01 does not employ preamplifiers.
Preamplifier Alarm Connector Definitions
PIN Description PIN Description
1 No Connection 6 PA Major +
2 No Connection 7 PA Major -
3 RS-232 TX 8 PA Critical +
4 No Connection 9 PA Critical -
5 Ground/Shield
4.6.5.4 RS-232 Connector
This port is configured for RS-232 serial communications. Refer to the DB9 figure and the RS-232 Connector
Definition (J20) table for pin location and definition. The RS-232 interface is located on the front of the amplifier
subrack. The purpose of this connector is to provide a system interface for upgrading firmware, displaying output
power and system status, and configuration. These tasks are performed using a PC with interface software. The
connector is a type DB-9. The RS-232 port is only enabled if pin 8 is grounded. Grounding pin 8 disables the two
RS-485 host interface ports. Standard 8-bit, 1-stop bit, no parity, 9600 Baud provides the appropriate interface
communication setting.
RS-232 Connector Definition (J20)
PIN Description PIN Description
1 No Connection 6 No Connection
2 RS-232 RX 7 No Connection
3 RS-232 TX 8 Select = 0 (grounded)
4 No Connection 9 No Connection
5 Ground
4.6.6 Pilot Tone Control
Refer to paragraph 4.4.5 for a full description of the amplifier pilot tone. The MCR21929-1-2 subrack can be used to
control the pilot tone frequency of the installed amplifiers. Pilot tone frequency selection is based on the intended