6. CONNECTION OF I/O UNITS TO
- This PCB can raise a confirmation sound when a key is pressed.
The condition to raise an audible alarm is set in 8-bit units, or in
*KYCn units. If *BZMD and common *KYCn are disconnected,
a KYnx input causes a sound to generate. If they are connected, a
KYnx input does not generate the sound.
To generate a confirmation sound for key input, the DO (PMC
address DO + 00.7) “MD07” must have been turned to “1” (see
1. A diode is necessary to connect *BZMD and *KYCn, as
2. This setting cannot be changed when power is supplied.
3. The sound is generated when the circuit closes between
common signal *KYCn and data signal *KYDx. It does not
sound when the circuit is disconnected. If key switches are
used, the sound is heard at the moment a key is pressed.
It does not sound when a key is released or when a key is
If *BZMD is connected to *KYC0 and *KYC2, but disconnected
from *KYC1 and *KYC3, as shown below, closing a switch at key
addresses KY10 to KY17 and KY30 to KY37 causes a
confirmation sound for key input to be heard, but closing a switch
at key addresses KY00 to KY07 and KY20 to KY27 does not.
See item “D Key switch addresses”.