- Sync the RTC of the Model T with your PC -

Are you tired of setting the clock on your old Model T Laptop?
Looking for an quick and easy way?
Looking for accuracy?
And you have a Windows PC with serial port and Internet synched clock?

Then you found the right tool for that job (granted you have the right nullmodem cable).

INTRODUCING: Model T TimeSync

This nifty tool automates the task of manually setting the clock by uploading a little BASIC program.
One that looks like this:
5 BEEP
10 OPEN "COM:98N1E" FOR INPUT AS 1
20 TIME$=INPUT$(8,1)
30 DATE$=INPUT$(8,1)
40 DAY$=INPUT$(3,1)
50 CLOSE 1
60 NEW

Yes, it looks neat and simple.
All what this does is: Beep the speaker, open COM port on the Laptop, set all clock variables after the incoming data, close COM port and delete itself from memory.

The tool on the other side after the BASIC program was uploaded and waits for CTS to go low (signaling that the upload completed) then waits for CTS to go high again (BASIC Line 10) to upload a Textstring containing the current date and time.

After you hear a beep and see no error on the Laptop means that the synchronization was successful.

This is so simple I'm quite astonished that nobody in the past decades wrote such a program.

There are 3 different versions:

• TRS-80 Model 100 (and M102 but that's not tested), US Olivetti M10 only
  (European M10 ROM uses DD/MM/YY)
  
• Tandy 200 (tiny changes like "COM:98N1ENN" and 1 second compensation)
  
• NEC PC-8201, PC-8300 (no support for weekday and uses "COM:9N81NN")

Sure, I'll could rolled all three versions into one single executable but I wanted to deal with one single commandline argument only... for certain reasons.

Now using this tool is very simple:
Before you start you should save your unsaved BASIC program in memory first if you care about that or else it will be gone forever.
1. Connect both sides with a fully populated nullmodem cable (with RTS and CTS lines).
2. Run RTC*.EXE with your COM port written as COM1 or \\.\COM10. (Like "RTC100.EXE \\.\COM15")
3. On the Model T you follow the instructions on the showed in the commandline window.
4. After the Model T beeped and the Time was set right, then you can disconnect the cable.

Download the ZIP here. (source files and Win32 binaries compiled with Open Watcom).

t-rtcsync.html © T. Sosnow.
Last updated: March 13, 2025 15:49

---