The latest model is turned on by pressing the center button, previous models have a power switch on the bottom. Since I currently have access only to the switch model so I will try to present some simple explanations for that one. I shall ask John Dedinsky, the clock’s producer, to supply some details for the latest model.

Turning the clock on with the red button simultaneously depressed will open the code menu.

Code to the codes most used in tournament chess:

CH is Tournament. ACT is action (G/30).

CH-DN is a 2 hr. time control followed by one or more 1 hr. time controls without a move counter, so the time for the next control is added when that for the first is used up.

CH-1 also may have unlimited 1-hour time controls, after the first 2-hour t.c. It shows a move counter. As soon as 40 moves are made by white that clock adds the next hour’s time. Same for black. When the player has less than 10 minutes the display will show a double dash and read minutes and seconds rather than hours and minutes.

CH-A1 is a delay mode with original setting of 4 minutes with 5-seconds delay. Be forewarned that this is a blitz mode and, in case of penalty, time cannot be reset during a game.

CH-A2 is a delay mode with one 90-minute t.c. and a 5-second delay preset. This, of course, can be reprogrammed. It can also be reset during a game, making it useful when inserting a time delay clock on a game for an ILC claim.

DL are delay modes (DL is displayed as dl—lower case; all are pre-set with 5-second delays). dl-1 uses one t.c., no move counter; dl-2A uses two t.c.s, no move counter; dl-2B uses two t.c.s, no move counter but displays the delay seconds (when under one hour) as they count down. dl-C2A is two t.c.s with move counter displayed throughout; dl-C2b is two t.c.s with move counter displayed only during the first t.c.

SD (displayed as Sd) is sudden-death, no time delay. Sd-2 is two t.c.s, Sd-3 is three, no move counter. Sd-C2A and Sd-C2b are two t.c.s with move counter.

Notes:

A colon, ":", separates minutes and seconds, as well as hours and minutes.

Some modes indicate flag-fall by three flashing bars on the side that falls. It does not necessarily freeze the clock (it may in some modes but I don’t think so). The CH-A2, for instance, shows only a line of 0s, the clock doesn’t freeze, and both "flags" can be down without knowing which fell first. Each mode can be programmed to beep at time control and/or flag-fall.

Stopping the clock: Press the red center button.

Resetting the clock: Short press the center button five times. Then, to scroll through the options, short press the center button. To back up, long press the button.

Changing displayed times: When reaching the desired mode, press the play button over that mode to activate it. Press the center button until the digits begin to flash. Use the play buttons on each side to alter the numbers displayed, the center button to advance to the next number. When the desired times are set, long press the red center button once.

The latest model has no on-off switch underneath. It is turned on, to the menu selection, by pressing the center button and both play buttons simultaneously. It is turned off by pressing the center button and the left play button five times.