Not communicating at all.

A.    For serial port connections, this plotter uses a null-modem 25-pin
      serial cable (CalComp part #19762-0107 10 ft. serial cable).
      
      1.    If the cable being used is from a CalComp pen plotter or TechJET
            monochrome 54xx plotter, then they have a straight-thru serial
            cable. A straight-thru serial cable with a null modem adapter
            (available at a local computer supply store) may be used .
      
      2.    The serial port on a PC is either a 9-pin or 25-pin male port
            (pins sticking out). Connecting a 9-to-25-pin adapter (available
            at a local computer supply store) is acceptable.
      
      3.    The serial cable must be no longer than 50 feet.
      
      4.    Verify that the settings on the plotter match the software
            driver:
            
            a.    Baud rate, number of bits, parity, stop bits=1, handshake
                  (use hardware or CTS if possible).
            
            b.    If using 907/PCI protocol, then verify sync char, # sync
                  chars, checksum, and end of buffer character.
            
            c.    Refer to the User's Guide  for a list of settings for
                  several applications.
      
      5.    It is possible that the port on their computer is not working.
            Additionally,  a PC with an internal fax/modem installed might
            have that port disabled.
            
            a.    Try connecting to a different port.
            
            b.    Try connecting to a different computer.
            
            c.    Try using a different serial cable.

B.    For parallel port connections, this plotter uses a standard Centronics
      parallel cable (CalComp part #18735-0129 10 ft. parallel cable).  The
      cable length maximum is 12 feet, unless it is a good quality double
      shielded cable. The 25-foot CalComp twisted-pair, double-shielded
      cables are the only longer Centronics parallel cables supported by
      CalComp (CalComp part #717960-9 25 ft. parallel cable).
      
      1.    Verify that the settings on the plotter match the software
            driver:
            
            a.    If using 907/PCI protocol, then verify sync char, # sync
                  chars, checksum, and end of buffer character.
            
            b.    Refer to the User's Guide  for a list of settings for
                  several applications.
      
      2.    It is possible that the port on their computer is not working.
            
            a.    Try connecting to a different port, if available.
            
            b.    Try connecting to a different computer.
            
            c.    Try using a different Centronics parallel cable.
      
      3.    This plotter uses the new IEEE 1284 Parallel Port Interface
            Standard.
            
            a.    This standard will become more popular as computer users
                  modernize their equipment. Unfortunately some IDE
                  Multipurpose Interface cards do not follow the recommended
                  backwards compatibility specification (12 milliampere
                  minimum).  The symptom is no sign of receiving data from
                  the computer's parallel port.  If this problem appears,
                  perform the following:
                  
                  i.    Try using a different computer.
                  
                  ii.   Try using a different parallel interface card with a
                        non-ECP parallel port.
                  
                  iii.  Some computer systems allow the parallel ports to be
                        configured as a non-ECP port via the computer setup
                        function on power-up.  If this choice is available,
                        select standard or bi-directional.
      
      b.    If this problem only appears with Windows 95, the port driver may
            have compatibility problems. Contact the computer manufacturer to
            obtain a replacement port driver. The file name of the port
            driver is LPT.VXD and is located in the System subdirectory of
            the Windows 95 directory (e.g., C:\WINDOWS\SYSTEM\LPT.VXD)