[Coco] Re: Coco printer primer...

[Torsten Dittel]

Hi Brian,
I copied the following info from and old CoCo FAQ I found using Google
Groups. You should use a "Courier" or similar non-proportional font to
read it. You have to connect the CoCo's /BUSY (or RxD) Pin 2 to the DTR
(Data Termninal Ready) Pin 20 of your printer interface. I'm not sure
about the handshake. XON/XOFF won't work and for RTS/CTS you might have
to place an additional bridge into the DB25 connector, but I would try
it first the simple way.

For further questions you might send me an e-mail offlist to:
os-9[at]trs-80[dot]cc for quicker response.

Best regards,
Torsten


--------------------

Q4) How do I connect a serial printer to the CoCo serial port? 


Serial I/O Connector Details for the Color Computer 


                   4-Pin DIN Connector MALE 
                          Rear View 


                               _____  Notch 
                              | 
                             \|/ 
                            __ __ 
                          /   U   \ 
              Pin 4 ---> | o     o | <--- Pin 1 
               Pin 3 --> |  o   o  | <-- Pin 2 
                          \ _____ / 


List of Materials: 
   1   DIN-4 connector, male (CoCo) 
   1   DB-25 connector, male (Printer connector) 
   6ft 3-wire cable (I got mine out of the same ribbon cable I 
       used to make my modem cable) 
Pinout: 


    COCO                    Serial Printer 
  DIN-4 pins                  DB-25 pins 
 ---------------------------------------- 
 CD   1 **** Not connected **** 
 RxD  2 --------------------- 20  DTR (Data terminal ready) 
 GND  3 ------------------+-- 7   GND (Signal ground) 
                          I 
                          +-- 1       (Frame Ground) 
 TxD  4 --------------------- 3   RxD (Receive data) 


4-Pin DIN to RS-232 (DB25) cable for PRINTER 


 DIN                                                   DB25 
=====                                                 ====== 
Pin 1 - Not Used 


Pin 2 - Ready signal from printer to computer ------- Pin 20 


Pin 3 - Ground --------------------------------------- Pin 7 


Pin 4 - Transmitted data from computer to printer ---- Pin 2 


Note:  The "Ready" signal is commonly referred to as the 
       "Busy" line in some printer manuals.  If your printer 
       does not provide a busy line, and you are using a CoCo 
       1 or a CoCo 2, you must connect this pin to a voltage 
       between +3 and +12 Volts DC to fool the computer into 
       thinking the printer is ready all of the time. 


Once you have the cable built, you need to set the printer's baud rate, 
serial interface protocol, and number of bits to match that of the 
CoCo.  For the DMP-130, that is done by setting 2 banks of DIP 
switches found in a slot under the ribbon's path. 


Once you have set the dip switches in the printer, configure your 
program to use the same settings (baud/parity/CR+LF/etc) as the printer. 
For example for baud rate on COLOR COMPUTER enter at command line: 
POKE 150,X - where "X" is one of the following poke numbers: 


POKE#     BAUD RATE 
 180         300 
  87         600 
  41        1200 
  18        2400 
   7        4800 
   1        9600