Service Guide N5230-90014 5-11
PNA Series Microwave Network Analyzers      Theory of Operation
N5230A Synthesized Source Group Operation
A16 Test Set Motherboard
The A16 test set motherboard serves these functions:
• to act as an interface between the A15 CPU board and the auxiliary rear panel 
interconnects.
• to provide ALC signals to the A19 SSLAM.
• to route control signals to the signal separation group. Refer to “Signal Separation 
Group Operation” on page 5-15 for more information.
Rear Panel Interconnects
The A16 test set motherboard includes the following rear panel interconnects.
TEST SET I/O A DB-25 female connector that is used to control external test sets. The 
external test set bus consists of 13 multiplexed address and data lines, three 
control lines, and an open-collector interrupt line. Pin assignments are 
listed in Table 5-3 on page 5-12. 
Up to 16 test sets may be “daisy-chained” on the bus at one time.
The Test Set I/O is not compatible with 8753 network analyzer test sets.
HANDLER I/O A rectangular 36-pin, female connector providing four independent parallel 
input/output ports, nine control signal lines, one ground, and a power 
supply line. This connector has Type 2 output pin assignments as listed in 
Table 5-4 on page 5-13.
All signals are TTL-compatible. Data input/output ports consist of two 8-bit 
output ports (Port A and Port B) and two 4-bit bidirectional ports (Port C 
and Port D).
Connector settings can be changed using SCPI and COM commands. The 
settings are not accessible from the front panel.
AUX I/O A DB-25 male connector that provides a variety of both analog and digital 
input and output signals as described in Table 5-5 on page 5-14.
I/O 1 (TRIG IN) A BNC connector for input of an external trigger. The analyzer can be 
triggered by an external device using this input. This is the same signal 
that appears on AUX I/O pin 19 as described in Table 5-5 on page 5-14.
I/O 2 (TRIG OUT) A BNC connector for output of a trigger signal. This trigger signal can be 
used to trigger external devices used in the measurement setup, such as 
signal generators.