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Operating instruction
Control panel SCD 1297-K
Page 53 / 64
DOC-Nr.: b40008de3.doc
3.2.2
Programming the LEDs
The foil keyboard has 39 LEDs which are arranged in combination with some of the keys.
These LEDs can be used, for example, as receipt or ready signals.
The LEDs are switched via the keyboard connection between the computer and the control
panel, in a similar manner to the programming of the keys. A special command has been
implemented for driving the LEDs since, in the MF2 specification; there are only NumLock,
CapsLock and ScrollLock LEDs. This command enables the individual LEDs to be switched
on and off.
The correlation between LED number and LED position is shown in Fig. 7, page 63.
The special command for the LED data is 0xEA followed by 10 Bytes with LED-Information.
Protocol
0xEA
B1H
B1L
B2H
B2L
B3H
B3L
B4H
B4L
B5H
B5L
0xEA
: Special command
B1-B5 : LED information in ASCII-Hex format (H= high, L=low)
Important: Each of the LED bytes, B1 to B5 is in ASCII hex format, i.e. for each LED byte,
‘Bx’, two bytes of data are transmitted.
For each byte that the control panel receives from the computer, a receipt byte (oxFA) is sent
back.