Operation (RS-232)
Sending and receiving data
The Model 7999-4 relay is RS-232 controlled. Before the relay can be controlled, connect
an appropriate and properly configured controller to the DB-9 port. The Model 7999-4 serial
interface (RS-232) transfers data using 8 data bits, no parity, and 1 stop bit (8-N-1). The
interface also transfers data at 9600 baud. Make sure that the controller selected also uses these
settings.
Termination characters
The Model 7999-4 can be configured to terminate each program message transmitted to the
controller with any of the following combinations of <CR> or <LF>:
<CR>
Carriage return (factory default setting)
<CR+LF>
Carriage return and line feed
<LF>
Line feed
<LF+CR>
Line feed and carriage return
To configure the termination character, change the jumpers for PA6 (J1006) and PA7
(J1008) located on the Model 7999-4 printed circuit board. Refer to Table 3-1 and Figure 3-2
for jumper details. Refer to the first three steps of disassembly information in Section 4 to
access the circuit board.
Table 3-1
Jumper positions—termination characters
Terminator
J1006 pins
J1008 pins
<CR>
1
1 and 2
1
1 and 2
1
<CR+LF>
2 and 3
1 and 2
<LF>
1 and 2
2 and 3
<LF+CR>
2 and 3
2 and 3
1
Factory default setting
Summary of Contents for 7999-4
Page 1: ...Contains Operating and Servicing Information Model 7999 4 Microwave Switch Instruction Manual...
Page 12: ...1 GeneralInformation...
Page 16: ...2 Connections...
Page 22: ...3 Operation...
Page 25: ...3 4 Operation 1 1 Figure 3 2 Jumper location...
Page 29: ...4 ServiceInformation...
Page 34: ...5 ReplaceableParts...
Page 38: ......
Page 41: ...Keithley Instruments Inc 28775 Aurora Road Cleveland Ohio 44139 Printed in the U S A...