Description:

Yellowbill is a free program provided to anyone who is looking for a powerful but easy to use SNTP client for Windows. Although designed for use with Intuitive Circuit's Cuckoo™, YellowBill will work with any NTP or SNTP server.

Basic features:

• Regularly sychronizes PC clock at rate you specify
• Immediately shows status of Time Server in system tray
• Able to log NTP packet information
• Gather statistics on time server operation
• Automatic detection of local time server
• Ability to generate test packets and see individual fields
• Monitor servers and run an external program if they lose GPS, shutdown, startup, etc.
• SNTP client only (see note below)
• Compatible with Microsoft Windows NT, Microsoft Windows 2000, and Microsoft Windows XP.

Important Note on SNTP vs. NTP Clients

YellowBill is an SNTP client, not an NTP client. Although the protocols are identical, and YellowBill will also operate with an NTP server, there are important differences of which you should be aware.

YellowBill does not consult multiple servers to get time, but just a single server. This means that it assumes that the first server it contacts will have an accurate time. It cannot average out differences in time offsets like an NTP client can. Although YellowBill provides the ability to set more than one server, these secondary servers are consulted for statistical or logging purposes only, not in the computation of system time. For a single local SNTP server like Cuckoo, this is not a problem because there will be low and controllable network latencies. However, if you are using YellowBill to set your time using an Internet NTP server, you may not achieve the desired system time stability or resolution.

Secondly, YellowBill sets the PC's clock immediately upon getting accurate time data from the NTP server. Unlike an NTP client, it does not slowly speed up or down (or slew) the clock rate to match true time. Slewing is done to prevent discontinuity in the clock, and prevents the clock from returning times that jump forwards or backwards. YellowBill does not slew the clock, but rather directly sets it. Because your PC's clock drifts at an independent rate, this means that when YellowBill synchronizes, your clock will jump ahead or behind slightly of to catch up to real time. Usually this is on the order of only a couple of milliseconds, but this causes small discontinuities at every synchronization point that some applications may be sensitive to.

If your concern for accurate time is on the order of seconds, rather than milliseconds, YellowBill will most likely meet your needs. But if you have any of the following needs, Intuitive Circuits would recommend using something other than YellowBill:

• Need to use with Internet NTP servers while still retaining subsecond accuracy
• Need for highly accurate PC time (within +/- 2 ms of true time)
• Need for PC's clock to represent time as a completely continuous flow
• Need for clock to never retrograde (hop backwards) for any amount of time, no matter how small

YellowBill can be configured so that it does not set the system clock. This is for those who would like to use YellowBill's other features, but have more exacting requirements on setting the PC's clock that require using another method.

YellowBill Screen Shots

If you want to see YellowBill in action, you should look at the YellowBill screen shots.

YellowBill Release Notes

Click here for release notes on YellowBill.

Warranty & Service:

If the product fails to perform as described in our product description or specification, within 1 year from the date of shipment to the buyer, we will repair or replace the product and/or accessories originally supplied. Failure due to improper installation, misuse, abuse or accident is not covered by this warranty. Incidental and consequential damages are not covered by this warranty.The buyer must obtain a Return Material Authorization by calling (248) 588-4400, and shipping the defective product to Intuitive Circuits, 3928 Wardlow Ct., Troy, MI 48083, freight prepaid. After the warranty expires, we will promptly supply an estimate for the repair cost.