Colorado Time Systems Handheld Segment Timer

The handheld segment timer, WHC-2, is a Colorado Time Systems (CTS) wireless controller that stores interval sets and runs them on a pace clock or a scoreboard over a 2.4 GHz radio link.¹ It holds ten sets of up to fifty repeats each and reaches any CTS multisport display that shows four digits of time, with no cable between the controller and the display and no timing console in the loop.¹²

Role in training¶

The segment timer holds the workout and the display only shows it. The pace clocks overview sets out the alternatives, which are a clock programmed at the unit itself, a timing console running a pace clock program, and the wired pace clock controller that preceded this one. Two things separate the segment timer from that console: its link needs no cable, and it fits in one hand.

When the controller is switched off, a clock that is still powered falls back to showing the time of day, which the segment timer can also set.¹

Design and controls¶

The controller is a battery-powered handheld with a screen and a keypad built around four arrow keys with an enter key at their center. Paging keys move the rep list a screen at a time, a plus and minus pair changes whichever value is highlighted, and separate start, stop, reset and cancel keys run a set. Power-on is a press and hold of the minus key; power-off lives in the menu and has no key of its own.¹

Two AA cells run it for about eight hours, and CTS recommends rechargeables.¹

The menu opens from a label above the rep display, highlighted with the arrow keys and confirmed with enter, and holds three items: the time-of-day setting, the wireless connection parameters, and power-off. It cannot be opened while a set is running, so the clock has to be stopped first.¹

Sets and reps¶

A set is a list of repeats, and the controller stores ten of them. Each set holds up to fifty reps, and every rep carries its own interval, so a set need not run one time over and over.¹

Every rep carries four settings:¹

• a duration entered as hours, minutes and seconds, with the hours field running to 99 and the minute and second fields to 59
• a direction, so that an individual rep counts up or counts down
• a beep of 0 to 9 seconds
• a position, since a rep can be moved up or down the order after it has been entered

At the set level the controller copies, pastes and clears, so a session built once can be duplicated into the other nine slots and edited from there.¹ Running a set means selecting its first rep and pressing start; reset restarts the current rep rather than the whole set.¹

The capacity is far below the pace clock controller’s fifty workouts of thirty sets, and the two are sold alongside each other, neither having replaced the other.³⁴⁵

Displays it drives¶

Any CTS multisport display carrying four digits of time will take the segment timer’s data.¹ What appears on it depends on the digit count. Four digits carry the current rep as a minute and second figure. Six give room for the rep number alongside it, so the swimmer reads the position in the set as well as the time running.¹

CTS names three display types: the slim pace clocks in both digit counts, the deck clocks, and the multisport portable scoreboards.¹ These are one addressable family rather than three unrelated products. The WA-3 guide defines it by part number: a multisport board is one whose part number opens with MS-, a class that takes in the deck clocks, the portable scoreboards and the multisport mini scoreboards. A label at the right-hand end of the enclosure carries it.⁶ The slim pace clock guide confirms the arrangement from the other end, listing the segment timer beside the WTTC-1 tabletop controller, the WHC-1 handheld controller and a CTS console as the four sources a clock will accept.²

One class of CTS pace clock is out of reach. The wireless pro, portable and standard pace clocks, and any clock converted by the K-PCW-1 upgrade kit, run on a radio with a front-panel channel switch and no network or module addressing at all.⁷⁸ Neither of those guides gives a band: they print only the FCC ID Q7V-3F090003X. The band comes from F941, which is titled for 900 MHz, identifies that same part as a Wi.232DTS, and reserves its channels 1 to 8 because CTS wireless pace clocks use them.⁹ Nothing in the CTS documentation states the consequence in one place, but a controller on 2.4 GHz cannot reach a clock on 900 MHz, so the segment timer and those clocks do not work together.

Wireless link¶

Three settings have to agree between the controller and every display it drives: the radio channel, 0 to 11; the PAN ID, which is the network number, 0 to 15; and the module address, 1 to 6, which picks out one display on that network.¹² A display announces all three when it is powered up, cycling them after a segment test, so the operator reads the values off the clock and enters the same ones on the controller.¹² Mismatch any of the three and the display receives nothing.¹

The channel and PAN ranges are the figures behind CTS’s marketing arithmetic: twelve channels and sixteen networks on each is the 192 simultaneous games the company advertises for this equipment.¹⁰ The WA-3 adapter is the exception, exposing eight networks on its switches where the rest of the equipment gives sixteen.⁶¹¹

Module 1 to 6 is a limit of the controller rather than of the displays. A deck clock’s own switch bank accepts addresses from 01 to 1E in hexadecimal, so a board can be set to an address no handheld can select.¹²

Three further items sit on the connection screen. A field labeled T-Level reports which generation of radio is fitted, a Version field gives the firmware level, and a program mode puts the controller into a state where its firmware can be replaced over the air, which CTS says to use only when its technicians ask for it.¹

Signal strength and troubleshooting¶

Opening the connection screen turns on a signal-strength readout, and the number appears on the scoreboard rather than on the controller. CTS gives its range as 24 to 64 in hexadecimal, so letters can appear among the digits, and says that a lower number is the stronger signal.¹

That reads backwards until the radio is identified. Digi documents the DB command on the XBee modules as returning the last packet’s received strength as the absolute value of a negative dBm figure, expressed in hexadecimal, so 24 corresponds to roughly -36 dBm and 64 to roughly -100 dBm.¹³ On that reading the controller is displaying the module’s own diagnostic register unchanged, and the scale counts upward as the signal weakens. CTS does not say this; it follows from the module’s documented behavior. The company describes the same readout as a measure of noise rather than of strength in its water polo instructions for the tabletop controller, keeping the direction but changing the explanation.¹⁴

When no number appears at all the fault is in the addressing, and CTS sends the operator back to the channel and PAN settings at both ends. A number that is high, or that stops updating, points at distance, interference, a damaged antenna on the receiving board, or the angle between the two units; the remedies CTS offers are to close the distance, to move both ends to a different channel and preferably to one end of the range, to check the antenna, and to reorient one of the units.¹

Radio and conformity¶

The controller does not hold an FCC grant of its own. It contains a certified module, and the manual names two: FCC ID OUR-XBEEPRO or MCQ-XBEE3, with the Canadian equivalents 4214-XBEEPRO and 1846A-XBEE3.¹ CTS also names the modules itself on the following line, as an xBeePRO or an xBee3 radio.¹ The registrations behind those names belong to MaxStream and to Digi International, for the XBee-PRO and the XBee 3, both 2.4 GHz modules on IEEE 802.15.4.¹⁵¹⁶ Digi bought MaxStream in 2006, so the two identifiers bracket one module family across its generations.¹⁷ That matches the connection screen’s radio-version field, which exists because either generation may be fitted.

The same pair of identifiers appears in the manuals for the WHC-1, the WA-3 adapter and the slim pace clocks, so one radio runs across the controllers, the adapter and at least some of the displays.¹⁸⁶² It is not the only radio CTS uses: the 900 MHz pace clocks and the 900 MHz wireless judging equipment carry a different module entirely.⁷⁹

The European declaration of conformity names model WHC-X where the product itself is the WHC-2, and the WHC-1’s manual carries the same wildcard, which is the clearest indication that CTS builds the two as one platform.¹¹⁸ The declaration is dated January 2019 and cites the low-voltage, electromagnetic compatibility, hazardous-substances and waste-equipment directives.¹

Documentation and availability¶

CTS lists the segment timer as a current product and supplies the F1050 guide and an instructional video from the product page.⁵ The guide is not on the company’s manuals index, which carries F970, F972 and F985 but neither F1050 nor the pace clock controller’s F901, so a buyer who looks in the obvious place will not find it.¹⁹ The infobox names the document without linking it for that reason.

Specifications¶

Type	Wireless handheld interval controller
Part number	WHC-21
Capacity	10 sets; up to 50 reps per set1
Rep duration	Hours 0–99, minutes 0–59, seconds 0–591
Rep beep	0–9 s1
Count direction	Set per rep, up or down1
Wireless	2.4 GHz15
Channel	0–111
PAN ID	0–151
Module address	1–61
Signal readout	24–64 hexadecimal, shown on the display; lower is stronger1
Radio module	FCC ID OUR-XBEEPRO (MaxStream XBee-PRO) or MCQ-XBEE3 (Digi XBee 3)11516
Power	Two AA batteries, about 8 hours1
Manufacture	Loveland, Colorado1

See also¶

• Pace clock controller: the wired controller that does the same job at greater capacity
• Slim pace clocks: the clocks it most often drives
• Deck clock: the multisport clock that doubles as a pace clock
• Multisport portable scoreboard: the third display type it addresses
• WHC-1: the scoring handheld built on the same platform
• WTTC-1: the tabletop controller for the same boards
• WA-3: the adapter that puts console data on the same radio
• Pace clocks: the pace clocks overview
• Colorado Time Systems: the manufacturer
• Equipment: the equipment reference

References¶

Footnotes¶

1. Colorado Time Systems, Wireless Handheld Segment Timer Controller User Guide (F1050 Rev. 202103, ©2021). ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹ ↩²⁰ ↩²¹ ↩²² ↩²³ ↩²⁴ ↩²⁵ ↩²⁶ ↩²⁷ ↩²⁸ ↩²⁹ ↩³⁰ ↩³¹ ↩³² ↩³³ ↩³⁴ ↩³⁵ ↩³⁶

2. Colorado Time Systems, Slim Pace Clock User Guide (F972 Rev. 202509). ↩ ↩² ↩³ ↩⁴ ↩⁵

3. Colorado Time Systems, Pace Clock Controller User Guide (F901 Rev. 1007, ©2007). ↩

4. Colorado Time Systems, Pace Clocks and Shot Clocks. ↩

5. Colorado Time Systems, Wireless Handheld Segment Timer (current listing, as of 2026). ↩ ↩² ↩³

6. Colorado Time Systems, 2.4 GHz Wireless Adapter WA-3 User Guide (F1045 Rev. 202007, ©2020), multisport board identification. ↩ ↩² ↩³

7. Colorado Time Systems, Wireless Pro Pace Clock and Shot Clock User Guide (F904 Rev. 202507). ↩ ↩²

8. Colorado Time Systems, Wireless Portable and Standard Pace Clock and Shot Clock User Guide (F910 Rev. 202008). ↩

9. Colorado Time Systems, Wireless Judging 900 MHz Frequency User Guide (F941 Rev. 20110720). ↩ ↩²

10. Colorado Time Systems, Complete Timing, Scoring, Training and Display Solutions catalogue (2015). ↩

11. Colorado Time Systems, WA-3 Wireless Scoreboard Adapter datasheet (12 channels, 8 networks per channel). ↩

12. Colorado Time Systems, Deck Clock User Guide (F985 Rev. 202007). ↩

13. Digi International, DB (Last Packet RSSI), returned as the absolute value in hexadecimal. ↩

14. Colorado Time Systems, WTTC Water Polo User Instructions (F1071), scoreboard signal readout. ↩

15. FCC ID OUR-XBEEPRO, MaxStream XBee-PRO OEM RF module (2.4 GHz ISM band). ↩ ↩²

16. FCC ID MCQ-XBEE3, Digi International XBee 3 (2.4 GHz, IEEE 802.15.4; IC 1846A-XBEE3). ↩ ↩²

17. Digi International, Form 10-K for fiscal 2006, MaxStream acquisition. ↩

18. Colorado Time Systems, Wireless Handheld All Scoreboards Controller User Guide (F970 Rev. 202103). ↩ ↩²

19. Colorado Time Systems, Manuals (F970, F972 and F985 listed; no F1050 or F901). ↩