Apple III Port C: RS-232-C Pinouts & Configuration (10/94)

Apple III Port C: RS-232-C Pinouts & Configuration (10/94)

The following table explains how use System Utilities to configure the driver for the RS-232 port (Serial Interface and Serial Card III). Remember to set the slot number on the Serial Card III driver.
Data Configuaration Blocks:
 
Data Configuration
Block Address:         $00
Baud rate:
  110                  $03
  134.5                $04
  300                  $06
  600                  $07
 1200                  $08
 1800                  $09
 2400                  $0A
 4800                  $0C
 9600                  $0E
 
Data Configuration
Block Address:         $00 $01
Data Format:
 Bits Parity
  8    none                $00
  7    odd                 $22
  7    even                $26
  7    MARK                $2A
  7    SPACE               $2E
  6    odd                 $42
  6    even                $46
  6    MARK                $4A
  6    SPACE               $4E
 
Data Configuration              *   *   *
Block Address:         $00 $01 $02 $03 $04 $05 $06 $07 $08 $09 $0A $0B
Comm Protocol:
none                                       $00
XON/XOFF                                   $80 $13 $11 $DF $84     $00
ENQ/ACK                                    $40 $05 $06         $50 $00
ETX/ACK                                    $40 $03 $06         $50 $00
HW Handshake                               $00         $DF $84     $80
 
* $02 - Delay after CR
* $03 - Delay after LF
* $04 - Delay after FF
 
Delays (bytes $02, $03, and $04)
 
Using this driver to connect to a printer may require that you set delay times while the printer advances to a new line or the top of a new page.  These delays are given in the range $00...$FF characters.  The RS-232 driver will wait for the time taken to transmit the amount of character specified before it sends the following character.
 
Pinouts: 
 
DB-25
Connector  Signal Name
 1 ......  Shield Ground
 2 ......  Transmit Data    (Tx)
 3 ......  Receive Data     (Rx)
 4 ......  Request to send  (RTS)
 5 ......  Clear To Send    (CTS)
 6 ......  Data Set Ready   (DSR)
 7 ......  Signal Ground
 8 ......  Data Carrier Detect      (DCD)
20 ......  Data Terminal Ready      (DTR)
 
Serial Card III has a modem eliminator button; when this button is "in", the above pinouts are correct.  If the button is "out", this has the effect of a modem eliminator cable being installed. (For more information on modem eliminator cables, search this database for MODEM AND ELIMINATOR.)


Article Change History:
12 Oct 1994 - Reviewed for technical accuracy. 

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