Pin		Type	Name					Description
1		Power	VGG						-12V Power Supply
2..3	Input	Ø2..Ø1					Clock Input
4..12	Input	Y1..Y9					Row Signal inputs from Keyboard Matrix.
13..20	Output	X1..X8					Column Interrogate pulses supplied by KEA to Keyboard Matrix.
21..23
24		Input	Repeat Oscillator		A low frequency square wave input to define the repeat frequency of the Strobe signal when in Repeat mode.
25		Input	Data Acknowledge		A input level or pulse which cause immediate reset of Strobe and Error signals.
26		Input	Buffer Reset			An input level or pulse causing immediate reset of all data Bits (D1 to D8) and the Parity Bit.
27		Output	Key Idle				An output signal indicating (when true) that no key is depressed on the Keyboard Matrix.
28		Output	Strobe					An output signal which becomes true at the beginning of the second scan following a scan
										in which a new key depression has been detected. The signal remains true until a new key
										is depressed, or the Data Acknowledge signal is received. The Strobe signal will alternate
										in synchronism with the Repeat Oscillator signal when operating in the repeat mode.
29		Output	Error					An output signal which becomes true at the beginning of the scan following a scan in which an error condition occurred. Error conditions include:
										1. Two new key signals in one scan.
										2. New key signals in two successive scans.
										The error signal, once set, remains true until: a new key is depressed; all keys are released; or the Data Acknowledge signal is received.
30		Output	Parity					An odd parity bit generated from the ROM data bits.
31
32..38	Output	Data Bit 7..Data Bit 1	Encoded data word output. All bits change to correct level simultaneously one clock period
										prior to generation of the Strobe signal. Data bit remain valid only for the duration of the
										Strobe signal (unless reset by activation of Buffer Reset signal).
39		Output	Data Bit 8
40		Power	VSS						+5V Power Supply