*STB?
Arguments: <none>
Function: Causes 944i to respond with its status byte.
Example: *STB?;
This status byte is also available through the serial poll and the serial poll method is recommended, as it is faster and less
processor intensive than the *STB? command. After this command is sent, wait 500 ms before checking status; the 944i's status
byte will then be valid and available in the output buffer. The byte is provided in binary format representing 0 through 32.
0x00 0001
High Voltage Present on Output
0x00 0010
End of Test Dwell Time
0x00 0100
Test in Progress
0x00 1000
Test Result Data Ready
0x01 0000
Test Terminated with Failure
0x10 0000
Undefined
x1xx xxxx
Set if SRQ Mask Enabled
1x00 0000
Undefined
*This bit not valid until test in progress bit has been set
Arguments: <serial number>
Function: Causes 944i to printout test results. The serial number of the DUT can be any ASCII string of up to 9 characters.
Example: PRINT,123456789;
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RS232 (Serial) Interface
The RS232 connector on the rear panel of the 944i is a 9 pin female sub-D type. The most common type of connector found on a
modern PC serial port is a 9 pin male sub-D type. The pinout of the 944i is designed to mate directly to a PC serial port using a
straight through 9 pin male to 9 pin female extension type cable.
Sending Commands
Data may be exchanged with the 944i serial port using the following protocol:
Baud Rate: 9600
Stop Bits: 1
Parity: none
Handshaking: no
Word width: 8
Echo Mode: echo off
Command Set for RS232
The command set available for serial operations is the same as that for GPIB (Except for the different read terminators and
command terminators noted above). You will notice that some commands are single words, but others consist of a root command
followed by one or more variables, also called arguments. Arguments may be used to set-up multiple items such as voltages,
currents, and test time. For commands with multiple arguments such as ADD and CNFG, the root command must be separated
from the first argument by a comma, and all arguments must be separated by commas.
"Query" commands, which usually end in a question mark, always provide a response to the query. Other commands are execute-
only commands that do not provide a response. It is recommended that a minimum 100ms delay be allowed following the last
command before sending a new command. You should experiment with different delays until you find a safe minimum delay
time between instructions.
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Parallel Printer Port
When the 944i is equipped with the optional IF-4 interface card, a centronix parallel printer port is included. The connector for
