5 It is unknown keyboard from Panasonic with Hirose Cherry M8 and 6P6C connector.
8 http://imgur.com/a/GAZE7
10 Hirose Cheery M8 switches:
11 https://deskthority.net/wiki/Cherry_M8
17 The keyboard is comprised of some of 4000 series IC without microcontroller.
20 RST>-----------+---------------+
23 --------- carry ---------
24 CLK>--->|row |------>|col |
34 ABC TC4512 vvvvvvv pull down
35 ---------- <----|+++++++|--100K--+
36 |data | <----|+++++++|--100K--+
37 STATE<--|selector| <----|+++++++|--100K--+
38 | 7 to 1 | <----|+++++++|--100K--+
39 ---------- <----|+++++++|--100K--+
40 row[0..7] | 8x8 matrix |
44 SENSE<----| OR |========+ OR'd row[0..7]
47 - TC4520BP - Dual Binary Up Counter
48 - TC4028B - BCD-to-Decimal Decoder
49 - TC4512BP - 8-Channel Data Selector
50 - TC4081BP - Quad 2-Input AND Gate
51 - TC4071BP - Quad 2-Input OR Gate
52 - TC4078BP - 8-Input NOR/OR Gate
58 --------------------------------------------------------------------
60 1 8 9 0 - ^ BS INS DEL
64 5 K L ; : RETURN UP F3 F4
66 7 SPACE , . / LEFT RIGHT DOWN HOME
73 2. Clock - sends clock to binary counter TC4520
74 3. Key State - indicates hi if key selected by counter is active
75 4. Sense - indicates lo if any key is active while Reset is hi.
76 5. Reset - resets counter and drives all column
89 AVR ATmega32u4 is used as protocol converter.
91 PD0: Clock. Counter couts up at falling edge.
92 PD1: Key State. Hi if selected key is activated.
93 PD2: Sense. Lo if any key is activated while Reset is Hi.
94 PD3: Reset. Resets counters at riging edge.