The Model T NIST Time Setting program By Peter Vollan 
(Documentation revised April 2011)(Edit December 2023) 

All modern portable devices automatically synchronize themselves to the correct time. On the TRS-80 Model 100, and computers closely related to it, the only way to set the time has historically been the "old fashioned way": by looking at a clock and typing it in. The NIST program sets the clock and calendar to the accurate time according to the NIST, the National Institute of Standards and Technology. This program is written for the TRS-80 Model 100 and the Olivetti M-10. Its companion program, TZONE.BA, is used to adjust the time to your local time zone.

The USA's National Institute of Standards and Technology disseminates accurate time information over shortwave radio, telephone recordings, and, fortunately for us, dialup modem lines which work all the way down to 300 baud. The NIST.BA time setting program uses the Model 100's internal modem and a telephone land line. You must connect to the PSTN through the "PHONE" connector on the laptop using a telephone interface cable. The internal modem dials using pulse (rotary) dialing. Local phone companies are required by law to support pulse dialing. So if you have a proper land line then pulse (or rotary) should work. 

The program makes a brief telephone call to the NIST dialup server in Boulder, Colorado. The NIST number is not a toll free number. The number is (303) 494-4774. (If you live in Hawaii, then you may wish to change the number to the NIST number in Hawaii: (808) 335-4721.) If you live outside of the North American Numbering Plan (NANPA), then you will need to add the digits necessary for making a call to the USA. 

When the modem connects. it alerts you with a tone. Then you should see progress indicators as the data is recieved and the time and date are set. When done, it will hang up the phone. 

The NIST uses Universal Coordinated Time(UCT), formerly known as Greenwich Mean Time (GMT). This is the time along the zero miridian which runs through Britain. To set the time to your local time zone requires the TZONE.BA time setting program. TZONE will prompt you for your offset from UTC. If you are in America ( I am referring here to the entire American continent ), the number will be negative. The number for my own time zone, Pacific Standard Time, is -8. Pacific Daylight time, in the summer, is -7.