Atari Interfaces/Connectors/Cables

last modified 14/01/2007 20:23


Désolé pas de version Française pour le moment
 

This page gives information on the numerous interfaces of the Atari ST and the associated connectors and cables. It also provides few information on some standard cables and connectors useful for the Atari ST. Most of the information related to standard cables and connectors comes from Handbook of hardware pinouts, cables schemes and connectors layouts & The Hardware Book as well as some other links. See also the Atari Cable document.


Table of Content


ATARI MIDI INTERFACE

The midi interface uses asynchronous signals (8 bits plus start and stop bits) at 31250 bauds (bit/sec). The Atari interfaces midi through a dedicated 6850 ACIA (Asynchronous Communication Interface Adapter) chip as shown below.

Atari Midi Connectors

The Atari has two midi DIN5 connectors: A standard Midi In connector, and a non standard Midi Out connector that also includes the Midi thru output (this was done to avoid adding a third connector as specified in the standard midi)

1 THRU Transmit data (non standard)
2 Shield Ground
3 THRU Loop return (non standard)
4 OUT Transmit data
5 OUT Loop return
Midi Out/Thru Pinout DIN5 Midi Out Connector
1 Non connected
2 Non connected
3 Non connected
4 IN Receive data
5 IN Loop return
Midi In Pinout DIN5 Midi In Connector

Note that the shield is only connected on the Midi Out connector and not on the Midi In connector, which is the standard way.

Standard Midi Cables

It is possible to use standard Midi cables for the Midi In and the Midi Out connection to/from the Atari. However it is mandatory to check that the cable connected to the Atari Midi Out does not have any wires connected to pin 1 & 3. This should be the case if you use a standard "midi cable" as describe below, but sometimes you will find DIN5 male-male cables that connects all the pins.

 

Male DIN5 @ cable

Male DIN5 @ cable
Name Male DIN 5 Male DIN 5
Shield 2 2
Data 4 4
Loop return 5 5

Atari Special Midi Out/Thru Cable

It is possible to build a special Y cable that allows to have a Midi Out port as well as a Midi Thru port coming from the Atari. Two cables goes from one male DIN5 connector (the one connected to the Atari Midi Out)  to terminate on a male DIN5.

 

Male DIN5 @ cable

Male DIN5 @ cable

Male DIN5 @ cable
Name Atari Out DIN5 Midi Thru DIN5 Midi Out DIN5
Thru sink 1 4  
Shield 2 2 2
Thru source 3 5  
out sink 4   4
out source 5   5

Picture of this cable


ATARI CARTRIDGE INTERFACE

This interface allows to use a ROM cartridge with a maximum size of 128KB. It connects the internal bus with the cartridge connector described below.

Pin

  Name  

Pin

  Name
1   + 5 VDC   21   Address 8
2   + 5 VDC   22   Address 14
3   Data 14   23   Address 7
4   Data 15   24   Address 9
5   Data 12   25   Address 6
6   Data 13   26   Address 10
7   Data 10   27   Address 5
8   Data 11   28   Address 12
9   Data 8   29   Address 11
10   Data 9   30   Address 4
11   Data 6   31   ROM Select 3
12   Data 7   32   Address 3
13   Data 4   33   ROM Select 4
14   Data 5   34   Address 2
15   Data 2   35   Upper Data Strobe
16   Data 3   36   Address 1
17   Data 0   37   Lower Data Strobe
18   Data 1   38   Ground
19   Address 13   39   Ground
20   Address 15   40   Ground


ATARI SERIAL INTERFACE

This interface is used generally for communication with other computers or with modems. Most of the connection comes from the USART (Universal Synchronous/Asynchronous Receiver/Transmitter) inside the MFP68901 with the exception of the DTR and RTS signals that comes from the I/O port of the sound chip.
The modem interface on Atari ST computers follows the RS232 standard apart from the following non-tested information: The CTS signal (that usually indicates that the modem is ready to take the next character) is connected to input I2 of the MFP68901 and generates an interrupts used by the system to start transmission. Therefore the CTS has to be pulsed (i.e. transitioned) for each character to send (in other word keeping it asserted does not work). As the RTS is pulsed for each character to send it can be directly connected to CTS. Again this is information coming from "the Atari ST bible" book and I did not verified it?


Serial Interface Connector

25 Pins D-SUB Male Connector

Pin Name Description
1 SHIELD Shield Ground. should not be connected to Ground
2 TXD Transmit Data
3 RXD Receive Data
4 RTS Request to Send.
5 CTS Clear to Send
6 DSR Data Set Ready
7 GND System Ground
8 CD Carrier Detect
9-19 N/C  
20 DTR Data Terminal Ready
21 N/C  
22 RI Ring Indicator
23-25 N/C  

Serial Interface Cables

Connection to a modem uses a normal modem cable (e.g. DB25F-DB25M or DB25F-DB9M).
Connection to another computer (e.g. a PC) requires a null modem cable (e.g. DB25F-DB25F or DB25F-DB9F).


ATARI PARALLEL INTERFACE

The parallel interface also called the printer interface of the Atari is somewhat standard but is missing many of the standard signals found on PC's parallel interface.

The printer signals are connected mostly on the Yamaha sound chip I/O ports! The only exception is the Busy signal that goes to input I0 of the MFP68901, and therefore a transition on this pin generates an interrupt.

The other signals shown in the schematic are used in the Audio/Video Interface (audio in and out) , in the floppy disc interface (drive 0/1, side 0), and in the serial interface (RTS, DTR)


Printer Connector

The Atari uses a standard 25 pins D-SUB Female connectors with the following pinouts (the last column shows for comparison a standard PC parallel interface)

D-SUB 25 Female connector

Pin ST Connector Standard PC Connector
1 STROBE STROBE
2 Data 0 Data 0
3 Data 1 Data 1
4 Data 2 Data 2
5 Data 3 Data 3
6 Data 4 Data 4
7 Data 5 Data 5
8 Data 6 Data 6
9 Data 7 Data 7
10 N/C Acknowledge
11 BUSY BUSY
12 N/C Paper End
13 N/C Select
14 N/C Auto feed
15 N/C Error
16 N/C Initialize
17 N/C Select In
18 GND Signal Ground
19 GND Signal Ground
20 GND Signal Ground
21 GND Signal Ground
22 GND Signal Ground
23 GND Signal Ground
24 GND Signal Ground
25 GND Signal Ground

As you can see the Atari I/F is missing the signals on pins 10 and 12 to 17.

Printer Cables

It is possible to use any "standard" printer cable with the Atari. Many of the wires are not used due to the fact that several of standard parallel port pins are not connected as already mentioned. Most printers from this time (like the EPSON LX800) where using a 36 CENTRONICS female connector. Therefore the most commonly used cable was the DB25M to CENTRONICS 36M printer cable.

Special Printer Cables

The printer interface provides an easily programmable bidirectional interface to the external world and was therefore used in several projects.

The PARCP Cable

The printer interface is used by several solutions to provide a fast communication channel between two computers (up to 100KBds).

Several of these solutions are using the PARCP cable:

  • The PARCP transfer program by Petr Stehlik (the origin of the name) [ ST/PC, ST/ST, PC/PC]
  • ST-Trans © Atari 1992 [ST/ST ]
  • Plip protocol of MiNT-Net © Kay Roemer
  • HDD_DMN3 by MC Soft & Hard [ ST/PC ]

A description of this cable can be found at the PARCP site. it is basically a DB25M-DB25M data-switch cable (all pins connected directly on both side) where wires connected to pins 1 and 11 are switched on one end. This results to data signals connected bit to bit and strobe from one side connected to the busy on the other side plus of course the ground.

Signal Name DB25 DB25 Remark
Strobe / Busy 1 11  
Data 0 2 2 10K resistor can be inserted
Data 1 3 3 10K resistor can be inserted
Data 2 4 4 10K resistor can be inserted
Data 3 5 5 10K resistor can be inserted
Data 4 6 6 10K resistor can be inserted
Data 5 7 7 10K resistor can be inserted
Data 6 8 8 10K resistor can be inserted
Data 7 9 9 10K resistor can be inserted
N/C 10 10 Connected or not
Busy / Strobe 11 1  
N/C 12-17 12-17 Connected or not
Grounds 18-25 18-25 At least one on pin 25

FYI: I have successfully used the PARCP program with this cable, but I did not succeed with HDD_DMN3, and did not try the other solutions.

Note that the data signals (pins 2 to 9) are connected to bidirectional ports on both side, and they are usually initialized to the default output mode (remember that usually a printer is suppose to be connected to this port) with an unknown value (i.e. 0 or 1). Therefore it is possible that any particular data bit from an output on one side is at 0 and on that the output on the corresponding other side is at 1 resulting in an electrical conflict. Electronic interface circuits are relatively tolerant but this situation should be time minimized by either setting the ports into the input mode during startup of the computers (some programs are provided as part of the PARCP solution for this matter), or by inserting a 1KOhm to 10KOhm resistor between each data signals. For that matter a 8x10K resistor pack can be inserted inside a connector on one side.

The BLITZ Cable

Used to make backup of "copy protected disk" : BLITZ uses ONLY a special cable and software to backup software, there is no internal wiring done to the computer. The BLITZ cable copies from Drive 1 out and through the computer printer port to drive 2 (you must have an external drive to use the BLITZ solution). It reads Drive 1 and writes Drive 2 at the same time. The BLITZ solution allows to backup protected and non-protected disks.

You need a Y cable with a DIN14F female connector on one side that will receive the connector from an external FD 'the drive 2). From this connector comes out two cables: one goes to a DIN14M connector that plug into the Atari FD connector, and the other one goes to a DB25M connector that plug into the Atari parallel connector.

The layout of the cable is the following:

DIN14M @ Atari FD DIN14F Connect to floppy DB25M @ Atari parallel con.
  1 - Read Data  
  2 - Side 0 Select 2 - Data 0
3 - Logic Ground 3 - Logic Ground  
  4 - Index Pulse 9 - Data 7
  5 - Drive 0 Select 3 - Data 1
  6 - Drive 1 Select 3 - Data 1
  7 - Logic Ground 20 - Ground (18-25)
  8- Motor On 7 - Data 5
  9 Direction In 6 - Data 4
  10 - Step 5 - Data 3
1 - Read Data 11 - Write Data  
  12 - Write Gate 4 - Data 2
  13 - Track 00 11 - Busy
  14 - Write Protect 8 - Data 6
Shield Shield Shield

Here is a picture of a blitz cable.


ATARI DMA INTERFACE

This interface allow to connect up to 8 external devices with a speed of up to 1MBytes / Sec. The interface is also called the Hard Disc interface because usually it it used to connect hard-disk, or the ASCI interface because it uses an Atari's proprietary hard drive connector/protocol similar to SCSI (which was standardized later) but unfortunately not directly compatible.

 

The DMA interface takes its name from the fact that it is connected internally to one of the Atari specially design circuit: the DMA circuit.

The main signals are:

  • A low asserted reset signal connected to the general reset of the Atari
  • A Chip Select CS
  • An Address bit A1
  • 8 bi-directional data bits Data 0 - Data 7
  • The R/W signal (signal high = write, low = read),
  • A low asserted Data Request DRQ input signal
  • An acknowledge
  • An interrupt request signal that goes to input I5 of the MFP to generate an interrupt.


DMA / Hard disk connector

The DMA/Hard disk interface uses an unusual D-SUB 19 female connector.

Pin Name
1 Data 0
2 Data 1
3 Data 2
4 Data 3
5 Data 4
6 Data 5
7 Data 6
8 Data 7
9 Chip Select
10 Interrupt Request
11 Ground
12 Reset
13 Ground
14 Acknowledge
15 Ground
16 A1
17 Ground
18 Read/Write
19 Data Request

Hard Disk Cable

To connect a hard disk like an SH204/205 or a Megafile you need to DB19M-DB19M Cable.

DB19M @ computer DB19M @ Hard Disk

All corresponding pins are directly connected (1-1 to 19-19)


ATARI FLOPPY DISC INTERFACE

As we will see the FD interface uses a very uncommon DIN14F connector. Most of the signals of this interface are connected to the Floppy disc controller chip (FDC) the Western Digital WD1772. Only few other signals are connected to the Sound circuit as shown in the parallel interface schematic.

 


Floppy Disc Connector

Pin Signal Name  FD Connector - DIN 14 Female
1 Read Data
2 Side 0 Select
3 Logic Ground
4 Index Pulse
5 Drive 0 Select
6 Drive 1 Select
7 Logic Ground
8 Motor On
9 Direction In
10 Step
11 Write Data
12 Write Gate
13 Track 00
14 14 Write Protect

Floppy Disc Cable

Usually external FD drive have a data cable coming out directly from the drive without connector. This cable is terminated on the other side by a DIN14 male connector that plug into the Atari FD interface.

I know also of a DIN14M-DIN14M cable used with the Discovery Cartridge. This cartridge associated with a specific program allow to backup "copy protected disks". In this cable all corresponding pins are connected directly: pin 1-1 to pin 14-14 plus of course the shield of each connector connected to the shield of the cable.  This cable is plugged on one side to the Atari FD connector and on the other side to Discovery Cartridge  DIN14F connector labeled Computer.

There is also a non standard cable to connect an external FD drive to the Atari called the BLITZ cable. This cable associated with a specific program allow to backup "copy protected disks".


 


ATARI VIDEO INTERFACE

The Atari video outputs are coming mainly from the Video shifter circuitry as shown below. Audio out and GPO are coming from the Yamaha YM-2149 sound circuit, and synchronization signals are coming from the Atari Glue chip.

Connection to the video circuitry

Atari Television Connector

Some Atari models have an RF modulator included (e.g. 520STFM) and a special connector for TV. You need to connect this output to your TV antenna and to tune your TV.

Core RF Modulated Video
Shield Ground
TV Pinout TV Out Connector

Atari Monitor Connector

This connector carry out the video signal as well as the audio in and out and a general purpose output pin.

1 Audio out: This pin is connected to the Atari sound output amplifier. It normally goes to the Atari monitor sound system, however if necessary it is possible to connect a 600 Ohms headphone on this output.
2 Composite synchronization: As the name indicates it is a combination of the V-Sync and H-Sync signals.
3 General Purpose Output: The GPO pin is connected to the pin 6 of the internal sound chip YM-2149 and can be freely programmed by applications. Usually not used
4 Monochrome detect: This pin is connected to pin 17 of the MFP68901 circuit and is used to set the Atari in Hi-resolution when grounded and to Med/Low-resolution when left open. A transition on this pin generate a reset of the system
5 Audio in: An audio signal on this pin is mixed with the Atari internally generated sound and the resulting signal is sent to the Audio output pin 1. Usually not used.
6 Green: This pin is connected to the green analog output coming from the shifter
7 Red: This pin is connected to the red analog output coming from the shifter
8 12V / 10mA pins. On 520STF this pin is actually connected to GND
9 Horizontal synchronization coming internally from the Glue chip
10 Blue: This pin is connected to the red analog output coming from the shifter
11 Monochrome: This pin is connected to the monochrome output coming from the shifter
12 Vertical synchronization coming internally from the Glue chip
13 Ground
Monitor Connector Pinout

DIN13 Monitor Female Connector

Pictures of the DIN13 female connector and male connector

Atari Video cables

SCART/Peritel Cable

This cable allow to connect the Atari to a TV with a SCART/Peritel input connector

Male @ cable Male @ cable

 Both connectors are shown from front and not from solder side

Signal Name Atari SCART Remark
Audio Out 1 6 (.2) Audio Left & Right
Composite Video 2 20 Composite sync
Monochrome Detect 4   Open
Green 6 11 Green in (through 150 Ohms resistor)
Red 7 15 Red in (through 150 Ohms resistor)
12V Pullup 8 8 Audio/RGB Switching
Blue 10 7 Blue in (through 150 Ohms resistor)
V-Sync 12 16 Blanking signal
GND 13 4.5.9.13 Ground

Notes:

  1. Some people advice to connect the RGB signals through 150 Ohms resistors. However looking at the Atari's schematics, the RGB output signal pass through 27 Ohm resistors on the STF and 75 Ohms resistors on the STE, and therefore I am not convince that adding extra resistor is mandatory. Actually all cables I have seen do not have these resistors.
  2. Connection of the audio out from Atari to pin 2 is not mandatory as pin 6 is the mono input.
  3. It is a good practice to connect the shield of the cable to the shield of the connectors on both side (but not to the GND!).
  4. Special thanks for information found here and here

VGA/SVGA Hi-res Cable

Male @ cable Male @ cable Male@cable

The table below indicates how to build a cable that setup the Atari in Hi-resolution mode and that carry the video from the Atari video connector to either a DB15 or DB9 VGA connector. Note that if you want to hear sound you need to have a separate cable coming out from the same Atari video connector to an audio connector (e.g. an RCA connector)

Signal Name Atari DB15 DB9 Remark
Audio Out 1     Audio connector
Monochrome Detect 4     Connect to pin 13
H-Sync 9 13 4  
Monochrome 11 1.2.3 1.2.3  
V-Sync 12 14 5  
GND 13 6.7.8.10 6.7.8.9  

You have to check carefully the pinout of the DB9 and DB15 connectors. Information can be found here and here.
The above cable describes the connection to a standard DB15 VGA pinout and a less standard DB9 early VGA pinout (e.g. in NEC Multisync 2)

CGA/EGA/Multisync Mid/Low-res Cable

Male @ cable Male @ cable Male@cable

The table below indicates how to build a cable that setup the Atari in Mid/low-resolution mode and that carry the video from the Atari video connector to either a DB15 or DB9 VGA connector. Note that if you want to hear sound you need to have a separate cable coming out from the same Atari video connector to an audio connector (e.g. an RCA)

Signal Name Atari DB15 DB9 Remark
Audio Out 1     Audio connector
Monochrome Detect 4     Open
Green 6 2 2  
Red 7 1 1  
H-Sync 9 13 4  
Blue 10 3 3  
V-Sync 12 14 5  
GND 13 6.7.8.10 6.7.8.9  

You have to check carefully the pinout of the DB9 and DB15 connectors. Information can be found here and here.
The above cable describes the connections to either a standard DB15 VGA pinout and a less standard DB9 CGA/EGA pinout (e.g. in NEC Multisync 2)

Atari Video Switch

Atari Monitors Switch

Male @ cable Females @ enclosure

If you have an SM124 High resolution monochrome monitor as well as an SC1224 color monitor from Atari then you need a monitor switch. This will allow you to switch from one monitor to the other without plugging/unplugging cables. You need a four circuits toggle switch and an enclosure (preferably a metal one) as well as a male DIN13 connector for the cable and two female DIN13 connectors to put on the enclosure.
The four circuits of the toggle switch are called A, B, C, D with the input being "in" and the output "1" & "2". For example Ain is connected to A1 if switch is in position 1 and to A2 if switch is in position 2 and of course the four circuits toggle at the same time.

Signal Name Male DIN13 Female Mono. DIN13 Female Color DIN13
Audio Out 1 1 1
Composite Video 2.Bin 2.B1 2.B2
General Purpose Output      
Monochrome Detect 4.Ain    
Audio - in      
Green 6   6
Red 7   7
12 Volts pullup      
Horizontal Sync 9.Cin 9.C1 9.C2
Blue 10   10
Monochrome 11 11  
Vertical Sync 1.Din 12.D1 12.D2
GND 13.A1 13 13

Position1 is the monochrome mode, position 2 is color mode. In summary the connection are:

  • RGB & Audio & GND are always connected from the input connector to the color output connector
  • Mono & Audio & GND are always connected from the input connector to the monochrome output connector
  • Composite Synch, H-Sync, and V-Sync are switched from the input connector to the mono or color monitor outputs depending of switch position
  • Monochrome detect of the input connector is switched to ground in monochrome position and left open in color position

This picture show an example of this kind of video switch.

Multisync Cable Switch

Male @ cable female @ enclosure

If you have a Multisync monitor that support the Hi-resolution mode as well as the Med/Low-resolution mode of the Atari ST (as explained in the FAQ) you need to build a special switch box that will allow you to switch between these two modes. The Multi Sync Monitor you plan to use on your Atari ST system must be able to accept the following Atari ST series computer range of Video outputs, TTL level Output of 1 Volt Peak to Peak (P-P) Video (R.G.B.) lines and 1 Volt P-P Audio Signal with a Horizontal /Vertical Synchronization and Scan frequency of: 15.75 kHz Horizontal, 60 Hz Vertical for Color display, 35.7 kHz Horizontal, 71.2Hz Vertical for Monochrome display. Note that a modern VGA monitor will work in monochrome position (and gives wonderful image compared to the Atari SM124) but will not work in color position (due to H-Synch less than 30 KHz) and this is the main reason for using a DB15 female connector. In order to connect to a DB9 monitor you need a "standard" DB15 to DB9 adaptor/cable

You need a four circuits toggle switch and an enclosure (preferably a metal one) as well as a male DIN13 connector connected to the cable and a female DB15 connector mounted on the enclosure.
The four circuits of the toggle switch are called A, B, C, D with the input being "in" and the output "1" & "2". For example Ain is connected to A1 if switch is in position 1 and to A2 if switch is in position 2 and of course the four circuits toggle at the same time.

Signal Name Male DIN13 Female DB15 Remarks
Audio Out 1  

audio connector

Monochrome Detect 4.A1    
Green 6.B2 2.Bin  
Red 7.C2 1.Bin  
Horizontal Sync 9 13  
Blue 10.D2 3.Bin  
Monochrome 11.B1.C1.D1    
Vertical Sync 12 14  
GND 13.A1 6.7.8.10  

Position 1 is monochrome mode, position 2 is color mode. In summary the connection are:

  • Audio goes to an audio connector fixed on the enclosure
  • H-Sync, V-Sync, and GND from Atari are always connected to  H-Sync, V-Sync, and GND of monitor input connector
  • RGB colors output from Atari are connected to RGB colors of monitor input connector in color position
  • Monochrome output from Atari is connected to the RGB colors of monitor input connector in monochrome position
  • Monochrome detect of the Atari is connected to ground in monochrome position and left open in color

Example Pictures (internals, closed) of the switch I made for my Multisync (note the connector for sound output)


ATARI MOUSE/JOYSTICK INTERFACE

The Keyboard Interface

Also not accessible from the outside the keyboard is connected to the main board through a connector. The keyboard, mouse, and joysticks are handled by a dedicated processor the 6301 that includes an internal ROM and RAM. The schematic of the keyboard shows how the keys and the mouse/joystick connectors are connected to the microprocessor. The keyboard communicate with the main system through a serial interface a 6850 ACIA.

The Mouse/Joystick Connectors

The Atari ST has two connectors under the keyboard to connect a mouse or joystick (port 0) and a second joystick (port 1)

The two connectors are DB9M connectors

Mouse/Joystick - Port 0 Joystick - Port 1
1 - Up / XB 1 - Up
2 - Down / XA 2 - Down
3 - Left / YA 3 - Left
4 - Right / YB 4 - Right
5 - NC 5 - Reserved
6 - Fire / Left Button 6 - Fire Button
7 - +5VDC 7 - +5VDC
8 - Ground 8 - Ground
9 - Joy 1 Fire/Right Button 9 - NC

Mouse/Joystick Switch

Accessing the mouse/joystick connectors is not easy as it is located under the keyboard. However as all programs uses a mouse and most games uses the joystick it is necessary to unplug the mouse and plug the joystick each time you want to play a game and vice-versa. This is obviously not very practical and therefore it is recommended to buy a mouse/joystick switch that allow to connect permanently two joysticks and a mouse and to select with a switch between the mouse and joystick on port 0. This following picture shows this kind of switch.


ATARI STE STEREO AUDIO INTERFACE

The Atari STE has two RCA Audio output ports for stereo (labeled left and right).


ATARI STE JOYSTICK INTERFACE

The Atari STE has two joystick DB15F connectors on the left side of the system.

Port A Port B
01 - Up 0 01 - Up 1
02 - Down 0 02 - Down 1
03 - Left 0 03 - Left 1
04 - Right 0 04 - Right 1
05 - PAD 0 Y 05 - PAD 1 Y
06 - Fire 0 Button 06 - Fire 1 Button
07 - VCC (5V) 07 - VCC (5V)
08 - NC 08 - NC
09 - Ground 09 - Ground
10 - Fire 2 Button 10 - Fire 3 Button
11 - Up 2 11 - Up 3
12 - Down 2 12 - Down 3
13 - Left 2 13 - Left 3
14 - Right 2 14 - Right 3
15 - Pad 0 X 15 - Pad 1 X

Here you will  find an interesting usage of these ports to connect to a PC. From Leonard Site (SainT)


STANDARD CONNECTORS / ADAPTORS (Non-Atari Specific)

Below are presented few connectors which are not specific to Atari but useful to know for some specific cables

SCART/Peritel Connector

male @ TV female @ cable

 

Pin Name Description Signal Level Impedance
1 AOR Audio Out Right 0.5 V rms <1k ohm
2 AIR Audio In Right 0.5 V rms >10k ohm
3 AOL Audio Out Left + Mono 0.5 V rms <1k ohm
4 AGND Audio Ground    
5 B GND RGB Blue Ground    
6 AIL Audio In Left + Mono 0.5 V rms >10k ohm
7 B RGB Blue In 0.7 V 75 ohm
8 SWTCH Audio/RGB switch / 16:9    
9 G GND RGB Green Ground    
10 CLKOUT Data 2: Clockpulse Out (Unavailable ??)    
11 G RGB Green In 0.7 V 75 ohm
12 DATA Data 1: Data Out (Unavailable ??)    
13 R GND RGB Red Ground    
14 DATAGND Data Ground    
15 R RGB Red In / Chrominance 0.7 V (Chrom.: 0.3 V burst) 75 ohm
16 BLNK Blanking Signal 1-3 V=RGB, 0-0.4 V=Composite 75 ohm
17 VGND Composite Video Ground    
18 BLNKGND Blanking Signal Ground    
19 VOUT Composite Video Out 1 V 75 ohm
20 VIN Composite Video In / Luminance 1 V 75 ohm
21 SHIELD Ground/Shield (Chassis)    

VGA DB15 Connector

Male @ monitor cable female @ video card

 

Pin Name Description
1 RED Red Video (75 ohm, 0.7 V p-p)
2 GREEN Green Video (75 ohm, 0.7 V p-p)
3 BLUE Blue Video (75 ohm, 0.7 V p-p)
4 ID2 Monitor ID Bit 2
5 GND Ground
6 RGND Red Ground
7 GGND Green Ground
8 BGND Blue Ground
9 KEY Key (No pin)
10 SGND Sync Ground
11 ID0 Monitor ID Bit 0
12 ID1 or SDA Monitor ID Bit 1
13 HSYNC or CSYNC Horizontal Sync (or Composite Sync)
14 VSYNC Vertical Sync
15 ID3 or SCL Monitor ID Bit 3

EGA DB9 Connector

Male @ monitor cable female @ video card/monitor

 

Pin Name Description
1 GND Ground
2 SR Secondary Red
3 PR Primary Red
4 PG Primary Green
5 PB Primary Blue
6 SG/I Secondary Green / Intensity
7 SB Secondary Blue
8 H Horizontal Sync
9 V Vertical Sync

DB15 to DB9 Adaptor/Cable

This can either be an adaptor (usually DB15 male to DB9 Female) or a cable (DB15 male to DB9 male) which is used to connect an old monitor with a DB9 female input to the output from a computer with standard VGA DB15 female connector.

Signal Name DB9 DB15
Red 1 1
Green 2 2
Blue 3 3
H-Sync 4 13
V-Sync 5 14
GND 6.7.8.9 6.7.8.10


CONNECTORS & CABLES LINKS

Some links to sites that provide useful information related to cable and connectors ...

 


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