Teledyne 300 Troubleshooting the modem connection, Data Communications Software for a PC

The modem is configured as Data Communications Equipment (DCE), and may have additional signal requirements to enable transmission. See modem troubleshooting section below.

NOTE

Modems are especially difficult because they may have pins that need to be at certain EIA RS-232 levels before the modem will transmit data. The most common requirement is the Ready to Send (RTS) signal must be at logic high (+5V to +15V) before the modem will transmit.

The Teledyne API analyzer sets pin 8 (RTS) to 10 volts to

enable modem transmission..

Troubleshooting the 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.

Data Communications Software for a PC.

You will need to purchase a software package so your computer can transmit and receive on its serial port. There are many such programs, internally we use PROCOMM. Once you set up the variables in PROCOMM and your wiring connections are correct, you will be able to communicate with the analyzers. Make sure the analyzer is set up for 2400 baud (SETUP-MORE-COMM-BAUD) and that PROCOMM is set up as described in the "RS-232 Pin Assignments" Figure B.1.

P/N 02163G1 Teledyne API Model 300 CO Analyzer Instruction Manual - Page 113