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CIRCUIT DESCRIPTION
6-37
March 1999
Part No. 001-2009-600
Pins 25-26 UNUSED
Pins 27/59 -5V IN
This is the -5V input to the MPC from the power
supply via the Controller backplane.
Pins 28-29 +5V IN
Pins 60-61
This is the +5V input to the MPC from the power
supply via the Controller backplane.
Pins 30/62 +15V IN
This is the +15V input to the MPC from the
power supply via the Controller backplane.
Pins 31-32 GROUND
Pins 63-64
This is the ground connection to the MPC from
the power supply via the Controller backplane.
Pin 47 READ
Pin 47 is used with the MREQ line to read data
from the main processor and external memory.
Pin 48 WRITE
Pin 48 is used with the MREQ line to write data
to the main processor and external memory.
Pins 49-55 Unused
Pins 57-58
6.11.6 J1 COMPUTER CONNECTOR
J1 is the MPC connection to the computer or
modem.
Pin 1 Ground
Pin 2 Computer Tx
Pin 3 Computer Rx
Pin 4 Modem DCD
6.11.7 J2 MEMORY SELECT
J2 is jumpered to select either the Flash memory
or the EPROM memory. Flash memory is ultra-fast
data storage. The normal setting is pin 1 to pin 2.
Pin 1 +12V
Pin 2 U25, pin 1 Vpp
Pin 3 +5V
6.11.8 J3 BAUD RATE
J3 is jumpered to select the baud rate from the
computer to the MPC, these two baud rates must be
the same (see Figure 6-23).
To change jumper J13:
Power off the station.
Move P3 to the proper rate.
Power on the station.
6.11.9 S2/S3 HSDB SETTINGS
These switches configure; the HSDB for RS-485
or single-ended 5V operation, indicate if the Summit
repeaters are connected to existing repeaters or only
Summit repeaters, and if the repeater is an end
repeater termination. Refer to Sections 2.9 and 7.6.9.
6.11.10 J4 EPROM MEMORY LOADING
This jumper selects EPROM memory loading for
LTR systems. The LTR setting is pin 3 to pin 4.
6.11.11 J5 HSDB SPEED
J5 is jumpered to select the data bus speed. J5,
pins 2/3 select the LTR 12 MHz crystal.
6.11.12 J6 WATCHDOG
This jumper enables or disables the watchdog
timer for reset. Normal operating mode is P6 jumper-
ing J6, pins 2/3. This jumper should not be moved or
removed.