CLKSYNCH is a utility program which will "synchronize" the time on your computer with the time from a "time server" which typically run on an atomic clock. CLKSYNCH does this by using your modem to call theirs, then with the configuration information you provide ahead of time, set the time on your computer to the correct local time.

CLKSYNCH is written using PowerBasic v3.20 and various MASM 6.0 routines for raw speed in critical areas where it matters.