4000 (250-5000) Pinouts Faxback Doc. # 1445
Below are pin assignments for the Tandy 4000 :
GND = Ground NC = Not Connected * = Active Low Signal
Printer - DB-25 Female Floppy - 34 pin card socket
------------------------------- ----------------------------------
1 Strobe* 14 Auto Feed* 1 GND 2 RWC*
2 Data 0 15 Fault* 3 GND 4 NC
3 Data 1 16 Initialize* 5 GND 6 NC
4 Data 2 17 Select In* 7 GND 8 Index*
5 Data 3 18 GND 9 GND 10 Motor Enable 1*
6 Data 4 19 GND 11 GND 12 Drive Select 2*
7 Data 5 20 GND 13 GND 14 Drive Select 1*
8 Data 6 21 GND 15 GND 16 Motor Enable 2*
9 Data 7 22 GND 17 GND 18 Direction*
10 Acknowledge* 23 GND 19 GND 20 Step*
11 Busy 24 GND 21 GND 22 Write Data*
12 Paper Out 25 GND 23 GND 24 Write Enable*
13 Select 25 GND 26 Track 0*
27 GND 28 Write Protect*
Keyboard - 8 pin DIN 29 GND 30 Read Data*
-------------------- 31 GND 32 Side Select*
1 Keyboard Clock 33 GND 34 Disk Change*
2 Keyboard Data RWC = Reduced Write Current
3 NC
4 GND Battery - 3 pin header Speaker - 4 pin header
5 +5V ---------------------- ----------------------
6 NC 1 +Voltage 2 GND 1 Sound 2 NC
7 NC 3 NC 3 GND 4 +5V
8 NC
Serial Port - DB-9 Male Power Connector (3)
----------------------- -------------------
1 Carrier Detect 1 +12V (violet)
2 Receive Data 2 GND (black)
3 Transmit Data 3 GND (black)
4 Data Terminal Ready 4 +5V (red)
5 Signal Ground
6 Data Set Ready
7 Request to Send
8 Clear to Send
9 Ring Indicator