Black Box MD1641A Configuring Software for Your Computer, Software Configuration, AT &F9 &W0 CR

Chapter 3: Software Configuration

You can store the initialization string in nonvolatile memory. With your communications software open and connected to the modem’s COM port, type the initialization string in the terminal window, substituting a carriage return for ^M. To store the string, enter

AT &F9 &W0 <CR>

Now you can initialize your modem with the following simple string:

AT Z ^M

3.6 Configuring Software for Your Computer

You must configure your communications software to match your com- puter’s configuration. If the Series II Modem is connected to the COM2 serial port, you must tell the software you are using COM2. Another important parameter is the serial port baud rate. This is the speed at which your modem communicates with your computer, not the speed at which your modem communicates with another modem. When V.42bis data compression is enabled, you must have a serial port baud rate four times the transmission speed of the modem to fully optimize compression. So if your UART is fast enough, you should set the serial port baud rate to a minimum of four times the top speed of your modem.

If you have an 8250 UART, your most reliable serial port speed will be 9600 bps; if you have an 8250A or a 16450 UART, try 19,200 bps; if you have a 16550 UART or equivalent, a serial port setting of 115,200 bps can be set reliably.

3.6.1 Configuring Software for the Remote System

You must meet the requirements of the remote system for successful communications. Though the Series II Modem can automatically match the speed of the other modem, you must specify parameters such as type of flow control, break length, number of data bits, number of stop bits, and parity. If you set these parameters incorrectly with the remote system, gibberish will appear on your screen.

32