DOS and Windows v2.0c-1 Serial Line Connection Requirements
The DOS and Windows V2.0c driver normally
requires the following serial connections:
| Acronym |
Signal Name |
Signal
Function |
DB9 Pin # |
| RD |
Receive |
Controller
transmit |
2 |
| TD |
Transmit |
Computer
Transmit |
3 |
| Gnd |
Ground |
Ground |
5 |
| DSR |
Data Set Ready |
Controller has
power |
6 |
| CTS |
Clear to Send |
Controller Power
On Self-Test (POST) complete |
8 |
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 only checked if the driver
instructs the computer to ask the controller for its Power On Self-Test results; this
command is sent on the Td line.
- If the POST results are requested, the driver will
not load 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), the driver will not load. Using the -p- switch in the ELODEV
command line will disable the POST results check. In this case, the driver will load
regardless of serial line conditions, and a two wire connection may be used. This is
referred to as disabling hardware handshaking.
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