(Sourced from the Ultimate MSX FAQ) (Giovanni R. Nunes)
Female 50 pin connector
1:/CS1 2:/CS2
3:/CS12 4:/SLTSL
5: RSV(N.C) 6:/RFSH
7:/WAIT 8:/INT
9:/M1 10:/BUSDIR
11:/IORQ 12:/MERQ
13:/WR 14:/RD
15:/RESET 16: RSV(N.C)
17: A 9 18: A15
19: A11 20: A10
21: A 7 22: A 6
23: A12 24: A 8
5: A14 26: A13
27: A 1 28: A 0
29: A 3 30: A 2
31: A 5 32: A 4
33: D 1 34: D 0
35: D 3 36: D 2
37: D 5 38: D 4
39: D 7 40: D 6
41: GND 42: CLOCK
43: GND 44: SW1
45: +5V 46: SW2
47: +5V 48: +12V
49: SOUNDIN 50: -12V
Short description of the pins: (from Philips VG8235 manual)
1-ROM addresses 4000-7FFF select signal
2-ROM addresses 8000-BFFF select signal
3-ROM addresses 4000-BFFF select signal (for 256k ROM)
4-Slot select signal
5-Reserved signal line - use inhibited
6-Refresh cycle signal
7-CPU's WAIT request signal
8-Interrupt request signal to CPU
9-Signal expressing CPU fetch cycle
10-This signal controls direction of external databus buffer. Cartridges are selected and L level is output from each cartridge at data transmission time
11-I/O request signal
12-Memory request signal
13-Write timing signal
14-Read timing signal
15-System reset signal
16-Reserved signal line - use inhibited
17-32-Address bus signals
33-40-Data bus signals
41-Signal ground
42-CPU clock 3.579545MHz
43-Signal ground
44,46-For insertion/removal protect
45,47- +5V power source
48- +12V power source
49-Sound input signal (-5bdm)
50- -12V power source