Testing basic modem connectivity

To see if a modem connection is working properly with a basic level of functionality, you can issue modem utility commands from the command line directly to your modem. To do this, perform the following procedure.

1. Connect the modem to the COM port (/dev/tty00) using appropriate cabling.

2. Run the modem utility as shown in the following example:
   
   /usr/lib/uucp/modem com1 9600

   In this example we are using COM1 (/dev/tty00h) at 9600 baud. We use the tty01h, rather than tty01, because tty01h lets us use hardware flow control.

   You should see a connected message. If you are having trouble getting the connected message, try running cs in debug mode as described in ``Using the connection server in debug mode'' and examine the log for errors.

3. Once you can talk to the modem (that is, once you get the connected message from the modem utility), try dialing the phone using the command specified in your modem's owners guide. If you have a Hayes-compatible modem, try atdtnumber, where number is the number you want to dial. Listen to the call progress. Watch for any errors the modem may report, and respond accordingly.

   If the remote modem does not answer, then there may be a problem with the remote modem's configuration (for example, the remote modem is not configured for auto-answer). Check the remote modem using these steps before proceeding.

4. To check out incoming connectivity, stay in the modem utility. If you have a Hayes-compatible modem, enter a ats0=2 command to the modem. The modem should respond with the message OK.

   While still in the modem utility, have a remote system call in. On a Hayes-compatible you should see the RING message and then after two rings hear the phone being picked up. Again listen to call progress. At some point the pings and whistles should stop and you should see the message CONNECT from the modem.

5. If you still cannot get a connected message, check your cable, or buy an RS232 mini tester or breakout box and make sure that the CD (Carrier Detect) light on the side connected to your machine is turned on. If it is not turned on, then there may be a problem with your cable or modem.

   Modem types generally wait for a CONNECT message to come from the modem before responding with the connected message. All connection types look for Carrier Detect; this is a cable signal that must be high for cu or uucp to continue.

6. Once you have the modems talking you should be able to communicate. If you've placed the call (rather than received an incoming one), you should be able to proceed with your login process.

   If, once you are connected, you see apparently random characters displayed when you type something, you may have a problem with your character size or parity settings. This may also be seen as the remote system not quite responding to you (for example, when the login comes out fine but the remote system just doesn't want to respond to your login ID). See ``Speed, character size and parity settings'' for more information.

7. Type a tilde and a dot (~.), then press the <Esc> key to exit the modem utility gracefully. (It is important to exit the modem utility gracefully; see ``Utility for testing basic outgoing connectivity'').