Agilent Technologies 8753ET User Manual page 109

Making Measurements
Using Test Sequencing
Pin 22 (TTL 1) on the TEST SET-I/O INTERCONNECT connector is a TTL line that
changes from TTL high to TTL low when changing TTL I/O FWD from 7 to 6. Refer to
Figure 1-68. To change from 7 to 6, press the following sequence:
• Press
TTL I/O
Changing the switch state back to the standard mode requires a 7 to be entered in the
"TESTSET I/O FWD."
Pin 1 on the external switch must be grounded. It can be grounded to:
• the analyzer's chassis
• the front panel binder post
• the outer shell of the TEST SET-I/O INTERCONNECT connector
• a ground pin on the TEST SET-I/O INTERCONNECT connector (pin 7, 12 or 18). Refer
to Figure 1-68.
Pin C (common) on the external switch (8762B Option T24) must be connected to the test
set interface pin 14 (+22 volt line). Refer to
Pin 2 on the external switch, connects to pin 22 (TTL 1) on the test set interface.
The TTL I/O can control both of the external RF switches. Both must be cascaded in
parallel together. Changing the TTL I/O FWD from 7 to 6 will change the external RF
switch state. This changes the measurement capability from the network analyzer to the
external test measurement device. The TTL I/O FWD when changed from 7 to 6 will
reverse the process.
1-96
TTL OUT TESTSET I/O FWD
.
6 x1
Figure 1-68.