Testing basic direct line connectivity

For direct lines you can try the same low-level connection you used to test your modem in the previous procedure. As in the modem testing procedure, you use the modem utility.

Perform the following

1. Connect the COM1 port (or another appropriate port) to the remote terminal or computer using appropriate cabling (which usually includes a null modem).

   The easiest way to test a direct line is to use a dumb terminal (with a dumb terminal, for example, you only need to configure the terminal settings correctly). If you use another UnixWare 7 system to test the line, make sure to use the procedure in this section to set up a bidirectional port on the remote system.

2. Make sure that the character size, parity, and line speeds match on both sides of the connection (see Config(4bnu)). The modem utility uses a character size of 7 bits, even parity, and the speed that you specify on the command line.

3. Enter the modem utility:
   
   /usr/lib/uucp/modem com1 9600

   Once you get the connected message from the modem utility, any characters you type should appear on the terminal screen, together with any system responses.

   If you do not get a connected message, then the problem is probably due to the modem's failure to receive the Carrier Detect (CD) signal over the cable (which is the only thing cu and the modem utility look for before returning the connected message).

   All connection types look for Carrier Detect (CD); this is a cable signal that must be high for cu or uucp to continue. In a direct connection, this usually occurs because the other side raises the Data Terminal Ready (DTR) signal. Note that these two signals are swapped in a null modem.

   Check your cable, or buy an RS232 mini tester or a breakout box and see that the CD light (on the side right before it goes into your machine) is high. If the cable is all right, then there may be a problem with your hardware.

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

5. 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'').