This appendix shows the pinouts for the following cables:
Note - The back panel of the system unit has one 25-pin D connector (marked "A/B") providing functionality for two serial ports when used with the optional serial interface Y-cable described and shown later in this appendix. Port A on the Y-cable provides asynchronous and synchronous functionality. Port B on the Y-cable provides synchronous functionality. Direct connection of other types of cables to the back panel 25-pin D connector provides access to port A or port B only. The Y-cable is required for simultaneous access to both ports.
Note - Many peripheral devices can operate in either RS423 or RS232 mode. The serial ports on the SPARCstation 10 system are set to operate in RS423 mode, but they can be configured to operate in RS232 mode. See "Serial Port Requirements" in Appendix D for information about how to change the serial port jumpers. The owner's manual for the device specifies the device's operating mode.
You must use the optional serial interface Y-cable to utilize the full functionality of serial ports A and B at the same time on your SPARCstation 10 system. The serial interface Y-cable shown in Figure E-1 is available at extra cost as a separately orderable item.
Figure E-1 Serial Interface Y-Cable
Basic types of cables for serial devices include the following:
Both modem and null modem cables may connect to the optional serial interface Y-cable, which connects to the SPARCstation 10 system unit. See Figure E-1. You may also connect modem and null modem cables directly to the back panel serial connector if you do not need access to back panel serial ports.
Note - You must use shielded cables to maintain compliance with FCC, DOC, VCCI, and VDE radio frequency emission limits.
A modem cable is a type of serial cable used to connect a modem to a computer system. If you are connecting a Hayes or Hayes-compatible modem, you must obtain a cable with a male connector for the modem end and a male connector for the system unit end. The modem cable is connected to either of the system unit serial ports.
Figure E-2 shows a typical serial modem cable. You can obtain a serial modem cable from most computer dealers or computer supplies stores.
Figure E-2 Serial Modem Cable
On a serial modem cable, the pins in the connectors are wired "straight through." This means that the pins function identically on the two connectors at either end of the cable.
Data Terminal Equipment (DTE) typically includes terminals, personal computers, and workstations. The acronym DCE stands for Data Communications Equipment. Modems are a good example of DCE. The SPARCstation 10 system is a DTE device.
A modem cable connects the SPARCstation 10 system unit (DTE) to a modem (DCE). Since DTE and DCE devices send and receive through different pins, their signals will not "collide."
Figure E-3 shows the wiring of a serial modem cable that enables the SPARCstation 10 system unit to communicate with a Hayes or Hayes- compatible modem. If you obtain a serial cable wired like the one shown and connect it to the back panel connector either directly or by means of an optional serial interface Y-cable, you will properly connect a Hayes-type modem and a SPARCstation 10 system unit.
Figure E-3 Serial Modem Cable Wiring
Null modem cables are another type of serial cable used to connect printers, terminals, and other devices. Null modem cable wires are connected to the pins in the connectors differently from how they are attached in a modem cable. The cable should have a male 25-pin connector for the system unit end. The gender of the connector at the other end of the cable depends on the device you are connecting to the system unit.
You can obtain ready-made null modem cables from most computer dealers or computer supplies stores.
As an alternative, you can make a null modem cable. Simply connect a null modem converter to a modem cable, and then connect the null modem converter to the serial interface Y-cable. See Figure E-4.
Figure E-4 Making a Null Modem Cable
The serial null modem cable is designed for devices that send and receive data on the same pins. Like the SPARCstation 10 system unit, printers and terminals are DTE devices - both expect to send data on pin 2 and receive it on pin 3. Because both devices are trying to send and receive on the same wire, these wires must be crossed.
If your device uses pins 4 and 5, they must also be crossed. These pins send and receive signals that indicate when data is transferred between the two devices.
If you are making your own null modem cable, you must connect the wires as follows (see Figure E-5):
Figure E-5 Null Modem Cable Wiring
A null modem cable also disables certain features of a peripheral device by "jumpering" wires from one pin to another pin on the same connector. Figure E-5 shows pins 6 and 8 jumpered and then connected to pin 20. This is the same for both ends of the cable.
A cable that is wired like the one shown in Figure E-5 and connected to a serial interface Y-cable will properly connect a SPARCstation 10 system unit and a Wyse WY50 or a DEC VT100 terminal.
If you have some other type of device, you will have to consult the manual for the device to determine whether jumpering is necessary and which pins should be jumpered.
For the SPARCstation 10 system unit to communicate with devices that the system software does not support, you have to identify the devices to your system by using the methods described in Chapter 15, "Printer, Terminal, and Modem Software," in the Sun System and Network Manager's Guide. But first you will have to select a serial cable that enables the SPARCstation 10 system unit and the peripheral device to communicate.
Because each device is different, there is no general rule for selecting or creating a serial cable. To obtain the correct cable, you will need to know which of the serial port pins are active. The manual for the printer, modem, or terminal should specify the active pins and what type of signal is sent or received on each pin. It should also specify what type of cable is required.
You should also consult Figures E-6, E-7, and E-8. These figures identify the pins that the back panel serial connector and the optional serial interface Y- cable ports use. Not all pins are active. If a pin is not highlighted, that means it is inactive - it does not send or receive any signal.
To cable an unsupported device:
Peripheral devices are cabled to the system unit serial ports. This procedure applies only to serial devices.
The manual or your dealer should have this information. Modems are generally DCE devices; most terminals and printers are DTE.
Begin by trying the cables with the pin configuration specified earlier in this appendix. These cables work with most devices.
If these typical cable specifications do not work, see the device manual to determine which pins are active, and consult Figures E-6 , E-7, and E-8 for the active back panel connector and optional serial interface Y-cable pins. Tables E-1, E-2, E-3, and E-4 give additional pin specifications. You have to wire peripheral device cable connectors according to the needs of both the peripheral device and either the back panel serial connector or the serial interface Y-cable ports. You may succeed only after some experimentation.
Figure E-6 SPARCstation 10 Back Panel Serial Connector A/B
Figure E-7 Serial Interface Y-Cable, Port A (Active Pins Highlighted)
Figure E-8 Serial Interface Y-Cable, Port B (Active Pins Highlighted)
Table E-1 Back Panel Serial Connector Specifications, Pins 1-12
Table E-2 Back Panel Serial Connector Specifications, Pins 13-25
Table E-3 Serial Interface Y-Cable Port A Specifications - Asynchronous
Table E-4 Serial Interface Y-Cable Port B Specifications - Synchronous
