Galleon Frequently Asked Questions

TimeSync NTP FAQ

Q. What is NTP?
A. NTP is an Internet protocol for time synchronisation. For more details on it look at our NTP page.

Q. What is broadcast NTP?
A. NTP includes an option to broadcast a time signal.

Q. My LAN has no broadcast NTP, how do I set it up?
A. TimeSync NTP will run in a time server mode where it will broadcast the time from the PC on which it is run.

Q. Why are only some of the PCs being updated when I use broadcasts?
A. Time broadcasts are limited to the local subnet; make sure that TimeSync NTP is set up to broadcast to all the required subnets.

Q. Can I use TimeSync NTP with xntp?
A. Yes, you can use TimeSync NTP as a server for xntp clients.

Q. TimeSync NTP doesn't seem to handle daylight/summer time in Europe?
A. The windows Date/Time control panel must be set to the correct Timezone for your machine for TimeSync NTP to work properly. Make sure that this is correct.

Q. The NT version doesn't update the clock when nobody is logged in?
A. Use the setting->control panel->services to edit TimeSync NTP's start-up settings. Set the TimeSync NTP service to run under the 'AdmiNPLrator' account

Questions and issues during installation:

• Galleon Server GPS Clock

• Galleon Workstation GPS Clock

• Novell Clock Drivers

• TimeSync NTP Clock Drivers (Windows NT / 2000)

• Stand Alone Windows NT Clock Drivers

• Galleon Radio Clock, not obtaining time or poor signal strength

If the items covered above does not solve your problem then contact Galleon Systems Limited and a Customer Support Engineer will contact you as soon as possible..

• Contact Galleon Systems

Desktop Radio Atomic Clock and Remote Antenna Unit - Problem Sheet

• Connecting a Windows NT Server to the ARC Clock
• Clock does not pick up time, seconds continually count up
• In-adequate Signal Strength
• Clock has valid time, but antenna symbol has disappeared
• Signal Reception
• Possible causes of Interference to the Time Signal
• Remote Antenna Cable Specification
• Maximum antenna cabling distance for remote antenna unit.

Connecting a Windows NT Server to the ARC Clock

The ARC Clock is equipped with a serial interface with a standard 9 pin connector. Select an unused serial port of your PC, usually marked COM1 ... COM4, plug in the ARC Clock connector. To plug the ARC Clock connector into a 25 pin serial port connector you will need a 9 to 25 pin adapter. Your dealer can usually supply one.

Clock does not pick up time, seconds continually count up.

The clock will attempt to pick up the time signal for approximately 6 minutes after power on. The antenna symbol on the clock will flash when a reception attempt is being made. If the clock cannot receive the time within the 6 minute time period it will enter an idle mode. When the clock is idle the antenna symbol disappears from the display and the seconds count up. Further reception attempts will be made every hour until the unit picks up the time.

Solution: If the clock does not pick up the time, reposition the antenna until a good signal strength is achieved. The clock may be forced to attempt to receive the time signal by powering the unit off and back on or by pressing the reset button at the back of the unit. Possible causes of Interference to the Time Signal.

In-adequate Signal Strength

In order to synchronise to the time signal the clock requires good signal strength. When the clock is first powered on or reset an antenna symbol will appear on the clock display. To the right of the antenna symbol is a number of bars. The number of bars represents the current signal strength. The indicator must show at least 3 or 4 bars consistently in order to pick up a valid time.

Solution: If the signal is too weak, reposition the antenna until a good signal is achieved, this can sometimes be accomplished by rotating the clock through 45 degrees.. When the clock is receiving a time signal, the antenna symbol on the display will flash. It takes approximately 3-4 minutes to initialise the unit with a valid time. Possible causes of Interference to the Time Signal.

Clock has valid time, but antenna symbol has disappeared.

The antenna symbol disappears from the clock display when the time signal has been lost.

Solution: This indicates that the antenna may need repositioning to receive the time signal. See in-adequate signal strength above. Possible causes of Interference to the Time Signal.

Signal Reception.

The MSF signal can be received at distances upto 1500km from Rugby (Midlands, UK), where the signal is based. The signal covers all of the UK and parts of continental Europe. The DCF signal is based in Frankfurt and covers a range of 1500km which encompases most of Western Europe. The range of the MSF signal can be seen in the diagram below.

Possible causes of Interference to the Time Signal

• Domestic appliance without radio interference suppressers
• computer monitors closer than 2 meters away
• TV Receivers closer than 2 meters away
• Machinery with high HF leakage
• Poor atmospheric conditions (i.e. stormy weather)

As with your Television or Radio, you may have difficulties in receiving a strong signal because of position or atmospheric conditions. Electrical appliances, motors, TV's or computers may interfere with the reception. You may experience poor reception in low lying areas and in metal buildings.

Fault:
Clock does not automatically show correct time within 10 minuets after the battery has been inserted or power on.

Procedure:
Check the battery voltage, battery contact and polarity.
Re-position the clock, e.g. turn through 45-90 degrees, or put it near the windows then start several tests by removing for 1 minute then replacing the battery. Check to see if any HF interference source such as TV is close by.

Important notes
The performance of the clock is subject to its' ability to receive the radio signal that is transmitted from Rugby. Difficulty in reception will be experienced in metal clad buildings. Signal strength improves at night, it is recommended to leave the clock overnight with the battery inserted, ideally near a window if you are having difficulty setting it.
This clock will not function outside the U.K.
Please note that the Rugby transmitter is shutdown for maintenance the first Tuesday morning of every month, and during the summer the signal can be interrupted for up to two weeks in normal working hours after which the service will be restored.

Remote Antenna Cable Specification

0.2 mm four core security \ alarm cable is required between the antenna and clock unit. CAT 5 structured cabling can also be used.

Maximum antenna cabling distance for remote antenna unit.

The maximum cable length from the antenna unit to the clock unit is 150m. The recommended cable specification is 4 core alarm cable. CAT 5 structured cabling can also be used.

• Red 'Data' LED does not flash at 1 second intervals.
• Green 'Synch' LED stays on continuously.
• GPS Cabling Requirements
• Power Supply Requirements
• Signal Reception
• Maximum Cabling Distance
• Will the GPS antenna operate in a window

Red 'Data' LED does not flash at 1 second intervals.
The red 'Data' LED should flash at one second intervals to indicate that serial data is being sent from the GPS receiver.
Solution: Check that the microcontroller unit and the GPS antenna unit are both powered on. Check the cabling between the two connector boxes.

Green 'Synch' LED stays on continuously.
The green 'Synch' LED when on, indicates that the Microcontroller is waiting for the receiver to lock on to enough satellites to give the time.
Solution: On a new installation it could take a considerable amount of time for the GPS unit to lock on to enough satellites. It may help to reposition the antenna, so that it has a clear view of the sky in all directions (180 degrees).

GPS Cabling Requirements
0.2 mm six core security \ alarm cable is required between the two connector boxes in order to position the GPS antenna on a roof top. Cable rolls are available from Galleon Systems Limited on request.

Power Supply Requirements
The GPS unit requires two 12V centre positive power supplies. One power supply for the microcontroller unit and a further one for the GPS antenna.

Signal Reception
Providing the antenna has a good clear view of the sky in all directions, a GPS signal can be received anywhere in the world.

Maximum Cabling Distance
The maximum distance between the antenna unit and the GPS receiver unit is 1km, using 6 core cable. Cable rolls are available from Galleon Systems Limited on request.

Will the GPS antenna operate in a window

The GPS antenna requires a clear view of the sky for correct operation. A reduced view of the sky may not guarantee good signal reception. However, for most locations the GPS antenna will work correctly sited on a window ledge.

Galleon Workstation GPS Clock

• Overview
• Cabling Requirements
• Maximum Cable Distance
• Antenna Mounting Requirements
• Antenna Power Requirements
• Testing GPS Communications with the Host Computer
• Will the GPS antenna operate on a window ledge ?

Overview

The Galleon Workstation GPS receiver is a complete GPS receiver and embedded antenna designed for time synchronisation solutions. The receiver can obtain accurate time and position information anywhere in the World.

The GPS receiver will track up to 12 satellites at a time while providing accurate time information to a host computer. The receiver is housed in a black, water resistant case and designed to withstand rugged operating conditions.

The Galleon GPS Clock receives time and positioning information from Global Positioning Satellites, which can be used to accurately synchronise the time on computers.

The Galleon GPS clock has a number of advantages over similar radio based products. It can be used at any location all around the world; radio broadcasts have a strictly limited range. The GPS clock is less susceptible to interference. Provided the GPS antenna has a clear view of the sky, it is less prone to environmental obstructions.

Cabling Requirements

Five meters of cable is supplied between the receiver and the host PC. The cable from the GPS receiver plugs into a RS232 Com port on a computer via the 9 way 'D' type connector.

Maximum Cable Distance

Five meters of cable is supplied between the receiver and the host PC. The antenna cable can be extended up to a maximum of twelve meters.

Antenna Mounting Requirements

The GPS receiver must be mounted externally, using the supplied mounting plate, with a clear view of the sky.

It is therefore advisable that the host PC be sited as near as possible to a roof top location or external wall.

The cable must run from the host computer mounted internally, through a wall to the externally mounted GPS receiver.

Antenna Power Requirements

The GPS receiver is powered from a 12 V power supply, supplied. On power up it may take a number of minutes for the receiver to obtain a satellite lock.

The supplied host software provides GPS status and Synchronisation information

Testing GPS Communications with the Host Computer

If you are encountering communication problems with the GPS antenna, check that the unit is powered up and connected to the correct communications port on the host computer.

If problems persist, an easy way to test GPS antenna communications with the host PC is to use a terminal emulation program, such as hyper-terminal. Select the Com port that the GPS antenna is connected to and use the following settings: 4800 bits per second (baud), 8 data bits, 1 stop bit, no parity and no flow control.

The GPS antenna continuously sends back time and position information in data packets, each beginning with a '$' symbol and terminating in <CR>. Time information is provided by the $GPSV data packet.

Will the GPS antenna operate in a window

The GPS antenna requires a clear view of the sky for correct operation. A reduced view of the sky may not guarantee good signal reception. However, for most locations the GPS antenna will work correctly sited on a window ledge.

Windows NT Stand Alone Atomic Clock Drivers - Problem Sheet

• Overview
• Windows NT Installation
• Starting the NT Clock
• Error messages in Event Log
• Changing Clock Driver Options After Installation
• Setting the Time On Other Computers
• How accurate can the time be set on the host computer

Overview

The Windows NT Stand Alone Atomic Clock driver runs as a service on a Windows NT 4.0 machine. The driver will accept the time from the clock and update the system time on the computer that the driver is running on.

Windows NT Installation

To install under Windows NT. Start Windows NT and from the "Program Manager" execute the file Pcrsetup.exe that is contained in A:\pcrsetup.exe on the supplied disk. The following display will appear,

1. First select the COM's port you wish to use to communicate with the clock
2. Next select either UK British Summer Time or UTC.
3. Use the Clock Synchronisation box to enter in minutes, how often you wish to update your Server. This can be from 0 onwards.
4. The next box asks if you wish to log all updates. As this is a service you can log all the updates and view them in Event Viewer under Applications. The option variance allows the user to the server clock to tick naturally or by entering 0 , will not let the Server clock to fluctuate.
5. You can either enter your account and password during installation or in service manager. Finally click on install and the Exit

Starting the NT Clock

Now that you have successfully installed your NT Clock software, you must now start the service. To do that follow the instructions below:-

Open the Control Panel and click onto services. The following screen will appear:-

Scroll down until you come to PC Radio Clock, at this point double click the directory which will open another window displaying the following:-

Within this window select Automatic and if you haven't done so enter a valid account and click OK. After selecting OK the previous window will appear, simply select start, a message will appear telling you Windows NT is Attempting to start the service. Once it has completed starting the service you may exit services and control panel .

You have now completed your installation and the clock will synchronise your server as you have specified.

Error Messages in Event Log

The following messages generated by the Clock Driver may appear in the Application Event Log.

The service was unable to open the COM port. Another process may be using its interrupt.
The specified serial port was found but the resource was in use by another application.
Solution: Either specify an alternative serial port or release the resource.

The COM port read failed. The data below shows the windows error number.
A windows error occurred when reading the serial port.
Solution: This error usually denotes a windows configuration problem.

A valid time string was not received from the PC Radio Clock. The received string was …
The service was unable to communicate successfully with the atomic clock.
Solution: Check that the clock is plugged into the specified serial port. Check the connections to the clock. Check the clock is powered on.

The service was unable to set the system time. Check its logon account has permission to set time. The time was read as …
The service could not set the system time, usually because the account that the service is running in does not have permission to set the time.
Solution: Modify the account permissions using user manager.

The System Time has been changed by more than the specified variance. UTC changed from/to:
The system time was updated by more than the specified variance.
Solution: Possibly because the system time has been manually modified.

The PC Radio Clock has not received a time signal since 02:30.
The clock has lost time signal broadcasts.
Solution: Reposition the antenna until the time signal is regained. Possible causes of Interference to the Time Signal.

The battery in the PC Radio Clock is low and should be changed.
This message should only appear when a battery powered clock unit is used.
Solution: The batteries in the clock unit are low and require changing. Remove the clock unit from the host computer before changing batteries.

The PC Radio Clock has updated the System Time. UTC changed from/to: …
The system time has been successfully updated.

Changing Clock Driver Options After Installation.

The clock driver options can be modified after installation by running the PCRSetup.exe program from the supplied floppy disk. Options can be modified and then updated by clicking the 'update' button.

Setting the Time On Other Computers

The stand alone windows NT driver does not synchronise the time on computers across a network. The driver only updates the time on a single computer. TimeSync NTP can be used to set the time across a network.

How accurate can the time be set on the host computer

It is difficult to quantify the accuracy of time on any Windows based host computer due to the fact that most Windows platforms are multitasking. We aim for an accuracy of 20 milliseconds (0.020 seconds) or better.

Novell NLM Atomic Clock Drivers - Problem Sheet

• Overview
• Installation
• Configuring Arctime.NCF
• Running Arctime.NLM.
• Unloading Arctime.NLM
• Novell Clock Driver Errors and Warnings
• Common COM port IO address and interrupt settings.
• Compatibility with NetWare Versions
• Netware Server Setup
• How accurate can the time be set on the host computer

Overview

The Novell Clock Drivers can be used to synchronise the time on a Novell Netware server. Drivers are available for Netware 3.x, 4.x and 5.x. The driver will set the time on a 'Primary Reference Server' or a 'Single Reference Server'.

Installation

Install the NetWare driver by copying the Arctime.nlm and Arctime.ncf files from the supplied disk to the NetWare system directory. The files must be copied from the disk at a workstation to the Novell server.

The files ARCTIME.NLM and ARCTIME.NCF both need to be situated in the SYS:\SYSTEM directory on the file server.

To copy these from floppy disk in A drive (substitute the correct letter for A if drive name is not A) to the desired destination carry out the following procedure.

1. LOGIN to a workstation as SUPERVISOR.
2. Type F:
3. Type cd F:\system.
4. Type copy A:ARCTIME.* F:

The asynchronous I/O driver AIOCOMX.NLM is a driver written by NOVELL and should already be in the SYS:\SYSTEM directory.

Configuring Arctime.NCF

The file ARCTIME.NCF loads the NLM's required. It is an ASCII text file that should be configured by the user to suit their own hardware set-up.

The line

LOAD AIOCOMX PORT = 2F8 INT=3
Attaches the asynchronous I/O driver AIOCOMX.NLM to a serial port on the file server. The PORT and INT settings as shown above are the default PC settings for port COM2. If the port to communicate with the ARC Master Clock is to be COM1 change the line to

LOAD AIOCOMX PORT=3F8 INT=4

If the PC settings have been changed from these default values or the port requested is already in use a request will be made for the user to specify alternative values.

The line
LOAD ARCTIME 10
Installs ARCTIME.NLM. The command line parameter 10 is the time in minutes between successive attempts to update the file server clock. The value may be changed to suit the needs of the system.

Running Arctime.NLM.

After the ARCTIME.NCF has been set to suit the system hardware and all necessary software and hardware installation has been completed the ARCTIME.NLM can be loaded.

At the file server console prompt type.

ARCTIME

A new screen should be displayed with the following details:

ArcTIME NLM

NOVELL Netware Ver 3.x and Ver 4.x

Last time the system clock was updated:

12:04:15 On 19/8/94

(clock updates every 10 minutes)

Licensed to Company Name
Serial Number : XXXXXX
dd-mm-yyyy

In addition to the above displays warning messages may appear on the screen. When the ArcTime NLM is first loaded, if it is unable to take control and configure the specified port, or if a valid time signal is not received a warning will appear and the NLM will terminate. (If this happens AIOCOMX will need to be unloaded before attempting to load ARCTIME again.)

Once the NLM is successfully executing, a warning will appear in the following instances:

The ARCTIME NLM is now loaded and will update the file server clock at the time interval specified.

To move between displays press Ctrl-Esc which will list all the current screens available. Press 1 to return to the system console and the number of the ArcTime screen to go back to look at the latest received time

Unloading Arctime.NLM

If the ARCTIME.NLM is no longer required or if a configuration parameter needs to be changed the AIOCOMX and ARCTIME NLMs should be unloaded

To do this type
UNLOAD ARCTIME
and
UNLOAD AIOCOMX
at the file server prompt.

Novell Clock Driver Errors and Warnings

The following errors and warnings may be produced by the Novell NLM clock drivers.

!!! WARNING : An invalid time offset has been specified and will be ignored
A specified time offset must be in the range -12 to +12.
Solution: Modify the time offset specified in the arctime.ncf file.

!!! WARNING : Valid time has not been received since 2:30am !!!
The clock has lost time signal broadcasts.
Solution: Reposition the antenna until the time signal is regained. Possible causes of Interference to the Time Signal.

!!! WARNING : Battery Voltage is low !!!
This message should only appear when a battery powered clock unit is used.
Solution: The batteries in the clock unit are low and require changing. Remove the clock unit from the host computer before changing batteries.

Unable to obtain control of specified serial port
Check serial port connections and configuration then try again
(Unload AIOCOMX before retrying.)
The specified serial port is most likely being used by another NLM.
Solution: Either change the serial port specified in artime.ncf file, or the NLM using the serial port must relinquish control of the resource.

Unable to configure specified serial port
Check serial port connections and configuration then try again
(Unload AIOCOMX before retrying)
The specified serial port is not recognised by the operating system, and is most likely non-existent.
Solution: Change the serial port specified in artime.ncf file

Unable to update system time
Check system configuration then try again
The NLM cannot communicate with the atomic clock.
Solution: Check that the clock is plugged into the specified serial port. Check the connections to the clock. Check the clock is powered on.

Cannot update system time, time difference greater than 3 hours.
The NLM will not update the system time if there is a difference of more than 3 hours between the clock time and the operating system time.
Solution: Manually correct the system time using the SET TIME command from the console.

Common COM port IO address and interrupt settings.

IBM compatible PC use the following port and interrupt settings for COM ports.
COM1 Port = 3F8 Int = 4
COM2 Port = 2F8 Int = 3
Non-standard serial cards may utilise different settings, check the product manual for correct COM port information.

Compatibility with NetWare Versions

The NetWare driver front screen may indicate that the driver is compatible with NetWare3.x and 4.x. The NetWare clock driver is actually compatible with Netware versions 3, 4, 5 and 6.

Netware Server Setup

The NetWare server that the clock driver is to be installed on must be set up as either a Single Reference Server or as a Primary Reference Server.

How accurate can the time be set on the host computer

It is difficult to quantify the accuracy of time on any Novell based host computer due to the fact that Novell platforms are multitasking. We aim for an accuracy of 20 milliseconds (0.020 seconds) or better. The processing speed of the host computer also has an effect.

Windows NT / 2000 TimeSync NTP - Problem Sheet

• Overview
• Software Installation
• Debugging and Message Logging
• TimeSync Errors and Warnings
• GMT required all year round.
• Synchronising the time across sub-nets
• Broadcast NTP
• Unicast NTP
• Setting the time on clients
• Typical TimeSync NTP Settings
• Can I use NTP to synchronise Computers with Non-Windows based Operating Systems ?
• How accurate can the time be set on the host computer

Overview

The TimeSync NTP application is a client, server application that is used to ensure the correct time across a network of computers. The TimeSync application is based on Simple Network Time Protocol (SNTP) which requires TCP/IP as a medium for data transmission.


Software Installation

• To install the software drivers for windows NT, please proceed as follows:
• You must be logged on as an ADMINPLRATOR to install the software.
• Make sure all cables are properly connected and that your PC is turned on. Close all running programs, insert the driver disk into the 3.5" drive and execute the program A:\SETUP.EXE.
• To do so, click START in the task bar and choose, Run…". Then type in the command line a:\setup. Alternatively, you can execute SETUP.EXE also by double clicking the symbol ,,SETUP.EXE" in the corresponding Explorer window of drive A:
• Let the set-up program guide you through the installation process.

TimeSync NTP runs as a service in a system logon account. This ensures that the NTP service is available regardless of whether anyone is logged into the host machine. The status of the service can be viewed and controlled, if required, from the 'services' applet in the control panel. A separate 'TimeSync NTP' control panel applet is provided in the control panel to provide a user friendly way of configuring and controlling the NTP service.

Debugging and Message Logging

All TimeSync NTP error and information messages are logged in the application event log. This can be viewed from 'Start > Programs > AdmiNPLrative Tools > Event Viewer'. Ensure that the application event log is selected from the 'Log' menu item.

Enabling all the log options on the TimeSync NTP Information tab will provide maximum information in the Event log for debugging and problem solving. With all the log options set the application event log will quickly fill. As soon as any problem is solved, turn off debug and information messages.

TimeSync Errors and Warnings

The following errors and warnings may be produced by the Windows NT TimeSync NTP clock drivers in the application event log.

Can't open port …
The specified serial port could not be opened.
Solution: The specified serial port is most likely being used by another application or does not exist. Either change the serial port specified, or the application using the serial port must relinquish control of the resource.

No response from atomic clock.
The service cannot communicate with the atomic clock.
Solution: Check that the clock is plugged into the specified serial port. Check the connections to the clock. Check the clock is powered on.

Clock data incorrect length. Length = …, Data = ….
The service received an invalid message from the atomic clock.
Solution: This may be due to a communications error, or an incorrect serial port is specified.

Atomic Clock battery low.
This message should only appear when a battery powered clock unit is used.
Solution: The batteries in the clock unit are low and require changing. Remove the clock unit from the host computer before changing batteries.

Atomic Clock has valid time, but no signal reception.
The clock has lost time signal broadcasts.
Solution: Reposition the antenna until the time signal is regained. Possible causes of Interference to the Time Signal.

Atomic Clock has not synchronised with time signal.
The clock has not received a time signal broadcast to set its internal clock.
Solution: Reposition the antenna until the time signal is received. Possible causes of Interference to the Time Signal.

GMT required all year round.

If your PC's are required to be set to GMT, UTC or Zulu time continuously, without switching to BST (British Summer Time), deselect the Daylight Saving Time option in the windows time properties.

Synchronising the time across sub-nets

The time can be synchronised across entire sub-nets by entering the subnet broadcast address in the list of broadcast addresses on the Broadcast NTP/NTP tab. NTP broadcasts can be enabled by checking the 'Enable NTP Broadcasts' check box. The default broadcast frequency is 64 seconds, but this can be easily modified using the 'Broadcast Frequency' slider.

Broadcast NTP

NTP broadcasts can be enabled by checking the 'Enable NTP Broadcasts' check box. The default broadcast frequency is 64 seconds, but this can be easily modified using the 'Broadcast Frequency' slider.

Unicast NTP

Unicast NTP communication is set up by default and requires no configuration of TimeSync NTP to enable.

Setting the time on clients

In order to set the time on client machines the TimeSync NTP client software must be installed on each of the clients. NTP broadcasts must also be enabled on the TimeSync NTP server application. See Broadcast NTP.

Typical TimeSync NTP settings:

Main Tab:
Server: MSF, DCF, MSF, Server GPS, Workstation GPS

General:
Notify other applications when the time is set: Unchecked
Automatically change servers on failure: Checked
Automatically change servers on success: Unchecked

Setting the time:
Set the time: Checked
Maximum correction allowed: 1 minute
Allow correction of maximum size if larger: Unchecked
How often the time is set: Every 10 minutes
Adjust automatically: Unchecked

Broadcast NTP/NTP
Broadcast addresses: 255.255.255.255 (local subnet)
NTP Stratum: 1
Broadcast frequency: 64 secs
Enable NTP broadcasts: Checked
Multicast TTL: 31

GPS (if required)
Com port: 1
Speed: 4800 bits per second
NMEA wakeup: <not required>

Information:
Log information messages: Unchecked
Log warning messages: Checked
Log error messages: Checked
Log debug messages: Unchecked

Can I use NTP to synchronise Computers with Non-Windows based Operating Systems ?

Network Time Protocol (NTP) is a standard time distribution system, it can be used to synchronise the time on any compliant piece of equipment.

Novell 5 and above have a NTP client built in for time synchronisation. Linux clients are readily available. NTP can also be used to synchronise the time on many routers.

How accurate can the time be set on the host computer

It is difficult to quantify the accuracy of time on any Windows based host computer due to the fact that most Windows platforms are multitasking. We aim for an accuracy of 20 milliseconds (0.020 seconds) or better.

• Provides accurate timing for computers and computer networks.
• Confidence of a three year warranty for long term reliability
• World-wide operation.
• Ideal for transaction processing, time & attendance and access control applications.

The National GPS Network Resource from the UK Government intended for GPS-equipped surveyors, and Geographic Information Systems (GIS) developers who work with Ordnance Survey (OS) mapping. Includes the Passive Station Database, Active Station RINEX Data, and Coordinate Converter services.

http://safari.oreilly.com/?x=1&mode=toc&sortKey=title&sortOrder=asc&view=& This book gathers hundreds of example router configurations all in one place. In chapter 14, the authors provide information on configuring, running, and debugging NTP on your Cisco router. This link via O'Reilly's Safari network for online publications.

www.tycho.usno.navy.mil/time.html US Naval Observatory - Provides the official source of time for the US Department of Defense and the GPS system (Global Positioning System) and standard US time. The site is an official US navy web-site.