Copyright 1992 SolaComp Software. All Rights Reserved.
DISCLAIMER OF WARRANTY
THIS SOFTWARE AND ANY ACCOMPANYING MANUALS ARE SOLD "AS IS" WITHOUT WARRANTY OF ANY KIND, EXPRESSED OR IMPLIED. THIS INCLUDES, BUT IS NOT LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTABILITY OR SUITABILITY AND ACCURACY FOR A PARTICULAR TASK. THE USER ACCEPTS ALL RESPONSIBILITY FOR THE USE AND CONSEQUENCES ARISING FROM SUCH USE. UNDER NO CIRCUMSTANCES SHALL THE SELLER BE LIABLE FOR ANY DAMAGES OR COSTS, DIRECT OR INDIRECT, RESULTING FROM USE OF THIS SOFTWARE.
NOTE
This program sets the computer's clocks by placing a telephone call to one of two automated time services. These calls will be long distance for the majority of users. The time services will automatically drop the connection within a minute.
INTRODUCTION
TimeSync sets the DOS and hardware real time clock with the current date and time. This information is obtained from a telephone call to the United States Naval Observatory or the National Institute of Standards and Technology using a modem attached to the computer.
The United States Naval Observatory (USNO) is the source of official time for the United States through its Master Clock. This time is derived from the average of a number of highly accurate timepieces based on "atomic" processes such as the frequency of radiation emitted from cesium under specified conditions or from a hydrogen maser under specified conditions. The USNO is responsible for determination and distribution of
precise astronomical and timing data for use in activities such as navigation, global positioning, and scientific research. The United States Naval Observatory is located in Washington, D.C. (telephone area code 202).
The National Institute of Standards and Technology, formerly the National Bureau of Standards, provides scientific and technological services including time and frequency standards. These include radio stations WWV, WWVB, and WWVH, and the Automated Computer Telephone Time Service (ACTS). To achieve maximum accuracy, the NIST-ACTS system interactively changes the timing of its signal based on the round trip time delay between itself and a caller. If everything works perfectly, the accuracy of the time signal should be within two milliseconds of the "correct" time. Even if things are not perfect, an accuracy of 10 milliseconds can be achieved by many users. The National Institute of Standards and Technology Time and Frequency Division is located in Boulder, Colorado (telephone area code 303).
Several factors limit the accuracy and resolution with which the time is set within a PC compatible computer. The time signal is received over a telephone and through a modem. Such things as the transmission speed, the propagation delay between the computer providing the time signal and the receiving computer, and the delays internal to the modem all create some degree of error from the "correct" time. These errors (the NIST uses a nominal value of 45 milliseconds) are balanced against the resolution of the clocks within the computer. The DOS system time is based on 55 millisecond clock 'ticks' provided by a hardware timer. The real time clock inside an AT compatible, or on an add-on card in a PC/XT usually only provides a resolution of one second.
REQUIREMENTS
This program requires an IBM PC/XT/AT or compatible computer with a 1200 baud modem. A mouse is optional.
REGISTRATION
If you find this package useful, a registration fee of $7.50 would be greatly appreciated. Send check or money order to:
SolaComp Software
P.O. Box 4464
Lutherville, MD 21094
Inquiries may be directed to the above address or to User ID 70732,3556 on the CompuServe Information Service.
INSTALLATION
The following files are included in this package:
TIMESYNC.EXE - The time setting utility
TIMESYNC.DOC - This file
TIMESYNC.HLP - The on-line help file for TIMESYNC
TIMESYNC.ICO - An icon for use in Windows
TIMESYNC.PIF - A sample PIF file for Windows
Installation consists of setting up a directory and copying the files into it, or simply copying all files into an existing directory.
OPERATION
TimeSync will operate in one of two modes: batch or interactive. Batch mode simply calls the selected time service using the configuration information previously saved. Interactive mode allows the user to change default settings and save them to the configuration file.
The batch mode is accessed using command line options. The command syntax is:
TIMESYNC /B [ NIST | USNO ]
The "/B" option will select batch operation which simply uses the current configuration file to make the time call. If "NIST" or "USNO" is entered on the command line, that time signal will be used; otherwise, the default time signal saved in the configuration file will be used.
Interactive mode is the default. Simply enter `TIMESYNC' from a DOS prompt. The program is menu driven. The menu choices may be selected either using a mouse or pressing the [ALT] key and the highlighted letter. The [TAB] key is used to move among fields on a form. Where appropriate, the [ENTER] key is used to accept the current values and end entry on a form. The "Cancel" selection will terminate entry on a form without saving any changes which may have been made. The [F1] key may be pressed at any time for help.
There are four top level menu choices available: Settings, Call, Quit, and Help.
The Settings menu allows system specific information to be displayed and modified. The selections available are
Default Service, Time Zone, Com Port, Port Settings, Modem Strings, Save Configuration, and Reset Configuration.
The Default Service menu item allows the user to select either the NIST-ACTS or the USNO Master Clock as the default time service. This is the service TimeSync will call during batch operation if a service is not specified on the command line.
The Time Zone menu item allows the user to specify the time difference between local standard time and
UTC (Universal Coordinated Time), also known as GMT. For instance, Eastern Standard Time is 5 hours behind UTC. If the "Use Daylight Savings Time" selection is checked, the time will be adjusted to daylight savings during the proper time of the year. Areas that do not use Daylight Savings Time incude Arizona, Hawaii, and the easternmost part of Indiana. The USNO Master Clock signal doesn't include information about daylight
savings time, so if the time service selected is the USNO, the program will assume that daylight savings time is in effect between the first Sunday in April (2:00 AM local time) until the last Sunday in October (2:00 AM local time). The NIST signal includes daylight savings time information.
The Com Port menu item allows the user to specify the com port (COM1 through COM4) to which the modem is attached.
The Port Settings menu item allows the user to specify the base address and IRQ associated with a com port. The default values do not normally need to be changed. They are:
COM Base Address IRQ
------------------------------------------
1 03f8 4
2 02f8 3
3 03e8 4
4 02e8 3
The "Reset" button will set these values to their defaults.
The Modem Strings menu item allows the user to edit the modem command and status messages. While the default values should work for most "AT Command" type modems, the documentation provided with
the modem should be referenced in setting these messages. Information regarding these commands may also be found in various communications packages. Some are quite robust in their support for a wide range of
modems. One useful addition to the initialization string is the command "M0" which turns off the modem's speaker. This may be added before the "^M" at the end of the initialization string. The "^" (caret) character will cause the next character to be interpreted as a control character (e.g. ^M is a carriage return). The "~" (tilde) will cause an 0.5 second pause when encountered (this is usually used when switching the modem into command mode).
The Set XT Clock Cmd menu item allows the user to specify the DOS command used to set the real-time clock on a PC or XT compatible computer. On AT class machines the real time clock is built in, and may be
directly accessed. In PC and XT-type machines, the real time clock is often on an add-on card, each of which has its own method of setting the time. The input to this selection should be the DOS command used to set the hardware clock (e.g. "\util\setclock").
The Save Configuration command saves the configuration in a file in the same directory as the program.
The Reset Configuration command restores the configuration to the defaults built into the program.
The Call menu allows the user to call one of the time services. The selections available are the two time services which may be used: NIST and USNO.
The NIST command places a call to the {NIST}.
The USNO command places a call to the {USNO}.
Quit causes the program to terminate. If the configuration file has not been written and any items were modified, the user will be prompted to save the configuration file.
The Help menu provides information about the program. It contains the About item.
The About command displays information about the program.
