Super Serial Card: Description (12/96)



This article describes the Super Serial Interface Card.

This article has been archived and is no longer updated by Apple.

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.
Published Date: Feb 18, 2012