The Windows NT v3.10c driver normally requires the following serial connections:

• Touchscreen data is sent on Rd, and ground is always needed as a reference.
• DSR is used to indicate to the computer that the controller has power.
• CTS is used to indicate to the computer that the controller has passed its Power On Self-Test.
  • The latter two are checked when the driver instructs the computer to ask the controller for its Power On Self-Test results; this command is sent on the Td line.
• The driver will load, but the touchscreen will not function under ANY of the following conditions:
  • The POST results are not received by the computer;
  • Controller power is not indicated by DSR being high;
  • POST completion is not indicated by CTS being high.
• If a wire is broken, or only a two wire connection is being used (Rd and Gnd), it will be necessary to disable the POST results check (commonly referred to as "disabling handshaking") before the touchscreen can function.  See "Disabling hardware handshaking."