Description: Super Serial Card: Description (12/96)
Header: Super Serial Card: Description (12/96)

 Article Created: 15 July 1991
 Article Reviewed/Updated: 16 December 1996

 TOPIC -----------------------------------------------------------

 This article describes the Super Serial Interface Card.

 DISCUSSION ------------------------------------------------------

 Overview
 --------
 The Apple II Super Serial Card provides a configurable RS 232 interface,
 allowing an Apple II, Apple II Plus, or Apple IIe computer to exchange data
 with other computers, modems, printers, terminals, and accessories employing
 a bidirectional RS-232-C interface in serial format (one bit at a time).

 The Super Serial Card features an on-board switch allowing the operation of a
 printer, modem, or other serial device. This switch also eliminates the need
 for special connection cables such as modem eliminators.


 System Requirements
 -------------------
 To use the Apple II Super Serial Card, you need:
 * an Apple II, Apple II Plus, or Apple IIe computer system with an available
  expansion slot; and
 * a printer, modem, or other serial device.


 Technical Specifications
 ------------------------
 * Single Level: EIA RS-232-C
 * Connector Type:  DB-25 socket
 * On-Board ROM: 2K x 8 bit (2316 or equivalent)
 * ACIA: S6551 or equivalent
 * Baud Rate Selection: via on-board DIP switches (default) or via software
  commands
 * Data word format: 1 start bit, 1 or 2 stop bits, 7 or 8 data bits; odd,
  even, or no parity
 * Available baud rates: 50, 79, 110, 134.6, 150, 300, 600, 1200, 1800,
  2400, 3400, 9600, 19200
 * RS-232-C Signals Supported: RTS (Request to Send), CTS (Clear to Send),
  DTR (Data Terminal Ready), DSR (Data Set Ready), DCD (Data Carrier Detect),
  RXD (Receive Data), TXD (Transmit Data), (SG) Signal Ground.


 Internal Cable Pinout
 ---------------------
 10 Pin      25 Pin
 Connector   Connector   Signal Name

 pin  1      pin  1      Frame Ground
 pin  2      pin  2      Transmit Data
 pin  3      pin  3      Receive Data
 pin  4      pin  4      Request to Send (RTS)
 pin  5      pin  5      Clear to Send (CTS)
 pin  6      pin  6      Data Set Ready (DSR)
 pin  7      pin 19      Secondary CTS
 pin  8      pin  7      Signal Ground
 pin  9      pin 20      Data Terminal Ready
 pin 10      pin  8      Data Carrier Detect


 Pin Explanation
 ---------------
 FRAME GROUND: Provides electrical connection to give both devices connected a
 common frame ground. Usually tied to Signal Ground inside the cabinet of one
 of the devices.

 TRANSMIT DATA: This pin conveys serial data sent from the Super Serial card.
 This is one of the pins that may need to be crossed over if the peripheral
 device is a DTE. The MODEM/TERM plug can perform this crossover.

 RECEIVE DATA: This pin receives serial data sent from the device the Super
 Serial card connects the computer to. This is one of the pins that may need
 to be crossed over if the peripheral device is a DTE. The MODEM/TERM plug can
 perform this crossover.

 REQUEST TO SEND (RTS): This signal is used by the computer to ask the
 peripheral device if it is ready to receive computer data. Often a device
 such as a printer will ignore this signal (will not have a pin connected to
 it) because the signals primary use is to control half duplex modems.

 CLEAR TO SEND (CTS): This pin receives the peripheral's ready to receive data
 response to an RTS from the computer. Again this pin is used most often by
 modems.

 DATA SET READY (DSR): This pin receives the signal generated by the
 peripheral that indicates that the peripheral is turned on and ready to
 communicate. This is one of the pins that may need to be crossed over if the
 peripheral device is a DTE. The MODEM/TERM plug can perform this crossover.

 SECONDARY CTS: Some modems can transmit and receive on two channels (that is
 two separate communications on the same line). The Secondary CTS pin would be
 used to receive the peripheral's ready to receive data response to an RTS for
 the second channel from the computer.

 SIGNAL GROUND:  When this pin is connected between two RS232 devices it
 provides a common electrical level that the devices can reference the RS232
 signals to.

 DATA TERMINAL READY:  This pin becomes active when the computer and SSC are
 ready to go on line. This is one of the pins that may need to be crossed over
 if the peripheral device is a DTE. The MODEM/TERM plug can perform this
 crossover. Also this pin can be used for flow control protocol handshaking.

 DATA CARRIER DETECT:  This pin receives the signal generated by a modem when
 it senses a carrier on the telephone line. The SSC would then respond by
 telling the computer that data was going to be coming from the modem.


 Jumper Block
 ------------
 The jumper block has two positions, Terminal and Modem. The jumper block
 eliminates the need for special connection cables such as modem eliminators.


 Switches
 --------
 The fourteen switches, split into two banks named SW1 and SW2, are diagonally
 opposite the slot contacts. Holding the card so that the switches are at the
 top left, the two banks are arranged like this:

   SW1 1 2 3 4 5 6 7      SW2 1 2 3 4 5 6 7
   ON                     ON
   OFF                    OFF

 The markings SW1, SW2, ON, and OFF may not appear exactly as shown. If the
 lever on a switch is pointing towards the top of the card, the switch's
 contact is closed and the switch is ON. Use a sharp but soft point, like a
 pencil point, to move the levers.


 Switch 1
                       1   2   3   4
 Baud Rate:
     50                On  On  On  Off
     75                On  On  Off On
    110                On  On  Off Off
    135                On  Off On  On
    150                On  Off On  Off
    300                On  Off Off On
    600                On  Off Off Off
   1200                Off On  On  On
   1800                Off On  On  Off
   2400                Off On  Off On
   3600                Off On  Off Off
   4800                Off Off On  On
   7200                Off Off On  Off
   9600                Off Off Off On
  19200                Off Off Off Off

 Switch 2
                                       5   6
 Auto linefeed after CR:
  Enabled                              On
  Disabled                             Off
 Passage of interrupts from ACIA to CPU:
  Enabled                                  On
  Disabled                                 Off


 Mode Switches
 -------------
 The setting of the Mode switches (SW1 5 and 6) determines the function of the
 remaining switches in one of two modes, Communications mode or Printer Mode.
 Printer Mode includes two modes for printer PROM emulation.

 Switch 1
                                       5   6
 Mode:
    Communications                     On  On
    Printer                            Off On
    SIC P8 Emulation                   On  Off
    SIC P8A Emulation                  Off Off


 Communications Mode
 -------------------
 The remaining switches have the following functions:

 Switches SW1-7 and SW2-7
                   SW1    7    SW2    7
 Protocol:
  RS-232C                 On          Off


 Switches SW2-1, SW2-2, SW2-3, SW2-4
                   SW2 1   2   3   4
 Data format:
  8 data/1 stop        On  On
  7 data/1 stop        On  Off
  8 data/2 stop        Off On
  7 data/2 stop        Off Off

 Parity:
  None                         N/A On
  Odd                          On  Off
  Even                         Off Off


 Printer and Printer PROM Emulation Mode
 ---------------------------------------
 The remaining switches have the following functions:

 Switches SW1-7 and SW2-7
                                   SW1    7     SW2    7
 Protocol:
  Normal Clear to Send (RS-232C)          On           Off
  Secondary Clear to Send                 Off          On

 Switches SW2-1, SW2-2, SW2-3, SW2-4
                   SW2 1   2   3   4
 Data format:
  8 data/1 stop        On
  8 data/2 stop        Off
 Delay after carriage return:
  32 milliseconds          On
  None                     Off
 Line Width (Printer mode has no parity):
  40                           On  On
  72                           On  Off
  80                           On  Off
  132                          Off Off


 Important Information
 ---------------------
 There is a problem with using the Super Serial Card (SSC) terminal firmware
 at 1200 baud on an unenhanced IIe. The IIe 80-column card can't keep up with
 the data stream and eventually loses characters. Avoid this problem with
 faster, more sophisticated programs that can handle interrupts, such as
 Access II or third party terminal software. The proper terminal software also
 will allow use of the Extended Text Card with a modem at 1200 baud.


 Article Change History:
 16 Dec 1996 - Reviewed for technical accuracy, revised formatting.
 Copyright 1991-96, Apple Computer, Inc.
 Keywords: