Filter
Top Products
Teledyne API Model 200AU NO
X
Analyzer Instruction Manual, 02293, Rev. F
9-37
To troubleshoot a modem connection first disconnect the RS-232 cable from the Analyzer and
verify (use a DVM) that you are getting a signal on Pin 2 of the RS232 port on the Analyzer. The
signal will be between -5V and -15V with respect to signal ground (pin 5). If not, there is a
problem with the CPU board or the cable. This is the transmit (TD) signal out of the Analyzer.
This should then be connected to TD input on the modem, normally Pin 2. If the Analyzer is
equipped with a DTE/DCE switch, you may need to change its setting so the signal is on Pin 2.
Second: Go to the cable connected to the modem/terminal and verify (use a DVM) that you are
getting a -5V to -15V signal on Pin 3 of the cable. This pin should be connected to Pin 3 of the
Teledyne API Analyzer.
Third: (for modems) Check that the voltage level on Pin 8 of the Analyzer is between +5V and
+15V. This pin should be connected (through the cable) to Pin 4 of the modem.
Now set the baud rate of the Analyzer to the speed required by the modem and it should work. If
you are still experiencing problems, a cable adapter may be needed. Please contact the factory
for assistance.
9.3.2.2 RS-232 Diagnostic Procedures
There are several features of the M200AU to make connecting to RS-232 and diagnosing RS-
232 faults easier.
There are two LED's on the rear panel Connector Board which are connected to pin 2 and 3 of
the DB-9 connector on the board. If the switch is in the DCE position (default) the red LED is
connected to pin 3 of the DB-9 connector. When data is transmitted by the M200AU the red
LED will flicker, indicating data present on this line. When the M200AU is running, the LED
will normally be ON, indicating logic low. A one second burst of data can be transmitted over
the port by a command in the DIAGNOSTIC menu. Press SETUP-MORE-DIAG, then scroll to
RS232 OUTPUT. Each time you press ENTR the instrument transmits a 1 sec burst of lower
case "w"'s.
The green LED is connected to pin 2, if the switch is in the default DCE position. This is the pin
on which the M200AU receives data. The LED is ON if an outside device is connected. This
LED gets its power from the outside device. When data is being transmitted by the outside
device to the M200AU this LED will flicker.
When you are attempting to configure the RS-232 port, if either of the LED's go out when the
cable is connected, that generally means that there is a grounding problem. Switching the DCE-
DTE switch should fix the problem. See the schematic and assembly drawings in the Appendix.