(Sourced from the Ultimate MSX FAQ)
(Giovanni R. Nunes)

Female 50 pin connector

{{:schematics:msxcartpinout.jpg|}}


   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