- By visual inspection of photographs of AK125
- Additional traces conectivity information from varszegimarcell (geekhack name)
- and reasoning.
- TODO: Add photos and wiring graphs
-
HOST:
- Connects (straight through, we assume) to AK125 System, whatever that is.
- 12DC (3 pins) and ground (6 pins) in.
- 5 unknown pins that connect to the "HOST-SYSTEM" connector on the other side of the Breakout Box.
- It may be that some of the unknown pins are used for either "Scrn" selection or Workstation protocol choices. TODO: TBD
-
Desk PC/Workstation:
- Connects (straight through, we assume TBD) to AK125-Desk-PC-Workstation.
- All 9 pins are used.
- None of the pins is used to power the keyboard. (mine works fine only connected to the +12VDC in the Host connector.)
- Pin 6, +5VDC will be present if some of the following are atached: TODO: True?
- Workstation-Generic (it's pin 6)
- Workstation-PC-Mouse (it'pin 1) TBD: Does it actually provide power?
- Workstation-PC-KBD (it'pin 1) TBD: Does it actually provide power?
- Workstation-SUN (Sun pin 8, TBD: should provide power.) That 5VDC power is supplied by each computer.
- Keyboard TX and RX (pin 6) go to/come from both Workstation Sun and Workstation-PC-KBD at the same time. It doesn't make sense to have computers connected to both of these at once. Pick one (or none).
- Mouse TX (pin 7) goes to/comes from both Workstation Sun and Workstation PC-Mouse at the same time. Again, it doesn't make sense to have computers connected to both of these at once. Pick one (or none).
- PS/2 signals (pins 4,5) go to Workstation-Generic.
- PS/2 signals (pins 8,9) go to Desk-PC-KBD. So these are separate and you could operate separate Workstation/Desk-PC at the same time without conclict.
- TODO: The purpose and use of pin 1 is unknown, but it goes to (or comes from) pin 8 of Workstation-PC-Mouse.
-
Mouse
- Receives Mouse (PS/2) data in from the breakout box, AK125-Mouse.
- Passes the data back to the appropriate Desk PC or Workstation-Generic via this connector or uses the AK125-Desk-PC-Workstation connector for serial workstation protocol.
The AK125 Breakout Box, in conjunction with the keyboard logic is capable of being a two-port KVM. The ports are labeled "Desk PC" and "Wkst." Furthermore, there are three posible "Workstation" ports available on the breakout box: TODO: confirm this 1. Workstation-Generic, kbd and mouse 2. Workstation-PC-KBD & Workstation-PC-Mouse, together (RS232 communication) 3. Workstation-SUN, kbd and mouse (Sun Serial communication) The configuration / choice of which of these to select/use is done with the keyboad setup screens.
The AK125 Breakout Box is fairly simple, mostly just tying different pins on different connectors together. The AK124 keyboards, and I presume Breakout Boxes seem to be much more common. I have not confirmed that the functionality and design match, though the connectors are all labeled the same.
The complexity in the system is all handled within the keyboard. There are no "decision-making" circuits or controls in the breakout box.
The kmd-3 "breakout box" is a different system, with different connectors, contains many active components, and was created by a different company. It is unlikely that this document will be of much help there.
The basic AK125 Breakout Box functionality is as follows:
- Keyboard input comes from the keyboard's "Desk PC/Workstation" connector. It
uses 3 sets of lines to talk to the four possible computer configurations available:
- Desk-PC-KBD, pins 8 & 9 (PS/2)
- Workstation-Generic, pins 4 & 5 (PS/2?+ or RS232?- TBD)
- Workstation-PC-KBD, pins 2 & 3 (RS232 Serial communication)
- Workstation-SUN, pins 2 & 3 (Sun Serial communication)
- Mouse input comes in the Mouse IN (PS/2) connector and is sent, unchanged,
to the AK-125 Mouse connector. That connector is connected to the Mouse
connector on the keybord. From there the mouse signals use 3 sets of
lines to talk to the different computers available:
- Desk-PC-Mouse (PS/2), from the keyboard Mouse connector
- Workstation-Generic (PS/2), from the keyboard Mouse connector
- Workstation using either Sun Serial or RS22 Serial communication), from the keyboard Desk PC/Workstation connector
- There are 5 pins of unknown purpose and direction from the AK125 System connector to the HOST-SYSTEM connector.
- Power (+12VDC) is provided by the Power Supply connector.
Visual summary:
* Red for keyboard data
* Green for mouse data
* Black for power and other
- The Breakout Box is Simple.
- One IC (Hex Inverter): SN7406
- One 5VDC regulator: L7805CV
- Three bypass capacitors (for power systems)
- Two pull-up resisters on inverter output lines.
- 12 connectors, around the edge of the box.
- There is so little to this box that this document is almost enough to recreate it, perhaps with even more convenient (PS/2) connectors, or built-in conversion to USB.
- It handles 3 different serial communication protocols (see below for
additional details)
- Data and Clock (PS/2 protocol) input is through the lone PS/2 connector, output through two DB9 connectors.
- Full duplex, 2-wire (TX and RX) RS232 serial communications for keyboard
- Half duplex, 1-wire (TX) RS232 serial communications for mouse. Although this is also labeled with "RX" that direction appears not to be used.
- Inverted, 1-wire (TX) RS232 serial communications for simulating a Sun keyboard to a Sun workstation
- Inverted, 1-wire (RX) RS232 serial communications for simulating a Sun mouse to a Sun workstation
- The keyboard handles all the "smarts" of routing the generated (kbd) and pass-through (mouse) signals.
The main, required, voltage to power the AK125 kbd is +12VDC. The 12 volts needs to be applied to pins 12, 13, and/or 14 of the keyboard's "HOST" connector. (All three pins are tied together inside the kbd anyway.) When a breakout box is involved the 12VDC comes from the "AK125 System" connector of the box.
The 12VDC can, conceivably enter the box one of 2 ways:
- (Confirmed) through the Power Supply connector, or
- (Possible, unknown) through the HOST-SYSTEM connector. If the HOST-SYSTEM does provide +12VDC then there is no need for a power supply to be connected to the box. In fact it should not be connected.
- Regardless of the source of the 12VDC (Power Supply or HOST-SYSTEM) the 5 volts is derived from a 5 volt regulator powered by the 12 volts.
- The 5 volts are then used to:
- Power an SN7406 inverter
- Act, through a pull-up resistor, on the inverter output line going to the Sun RX/TX Mouse connector.
- Act, through a pull-up resister, on the inverter output line going to the Sun TX Kbd connector.
- Go to the +5VDC pin of the "Mouse IN" connector (PS/2), to power an external, shared, mouse.
- Workstation-SUN connector (Pin 8)
- Pins 6(?) of Workstation-Generic and
- other pins from Workstation-PC-KBD, and
- Workstation-PC-Mouse.
It seems that all go to pin 6 of AK125 "Desk PC/Workstation. TODO: Why? Perhaps it is used to detect Workstation presence?
TODO: Include more here. See summary for what to cover.
Earliest system, pre-PS/2. 1200 baud, fixed rate. One start and one stop bit. No parity. RS232 standard pin assignments, should they prove useful, are:
1 DCD
2 RX
3 TX
4 DTR
5 Ground
6 DSR
7 RTS
8 CTS
9 Ring indicator
Sun's take on RS232 Serial, where they invert the TX and RX signals. TTL levels. (+5VDC for zero, Ground for one) 1200 baud, fixed rate. One start and one stop bit. No parity. Sun standard pin assignments, should they prove useful, are:
Pin Function Signal/Voltage
--- -------- --------------
1 Ground 0V
2 Ground 0V
3 Power +5 Vdc
4 RX/TX Mouse
5 RX TTL
6 TX TTL
7 Ground 0V
8 Power +5 Vdc
Instead of transmitting at a fixed rate, say 1200 baud, the protocol uses one wire as a clock (cycles once for every bit) and the other for data (+5VDC = 1 bit, ground for zero bit).
Serial data at 10.0–16.7 kHz with 1 start bit, 8 data bits (LSB first), 1 parity bit (odd), 1 stop bit, [1 ack bit (if host-to-device)] When the host pulls the clock low, communication from the device is inhibited.
Starting at the top-left, and moving counter-clockwise.
The breakout Box includes 12 connectors as follows:
TODO: Add column: Direction WRT the box
| Type | Name, on case | Name, on PCB | Kbd connector name | Protocol | Dir'n |
|---|---|---|---|---|---|
| ? | Power Supply | (none) | N/A | In | |
| 8DIN-F | Workstation-SUN | Wkst-SUN 8-pos. | Sun | Out | |
| DB15-F | AK125 System | AK125 "HOST" | Host | N/A or unknown | ?? |
| DB9-M | AK125-Desk-PC-Workstation | AK125 "Desk PC/Workstation" | Desk PC/Workstation | PS/2, Sun | In |
| PS/2-F | Mouse IN | Mouse IN 6-pos. | PS/2 | In | |
| DB9-F | AK125-Mouse | AK125 "Mouse" | Mouse | PS/2 | In/Out |
| DB9-M | Desk PC-Mouse | Desk PC-Mouse | PS/2 | Out | |
| DB9-M | Desk-PC-KBD | Desk PC KBD | PS/2 | Out | |
| DB9-M | Workstation-PC-KBD | Wkst-PC-KBD | Serial | Out | |
| DB9-M | Workstation-PC-Mouse | Wkst-PC-Mouse | Serial | Out | |
| DB9-F | Workstation-Generic | Wkst-Generic | PS/2 | Out | |
| DB15-M | HOST-SYSTEM | System | Unknown | ?? |
- Power supply: 12VDC
- Mouse-IN: PS/2 mouse data enters the breakout box, is sent to the kbd via AK125-Mouse, and distributed back to either the DESK-PC-Mouse or Workstation-Generic connector.
- AK125-Desk-PC-Workstation: Keyboard (typed) data, and serial mouse data. (But not PS/2 mouse data.)
- Workstation-SUN: Kbd and Mouse data heading for a Sun Workstation (CPU). The Sun thinks it's coming from a local keyboard and mouse.
- Desk-PC-Mouse: Mouse data flows to PS/2 connector on desktop system.
- Desk-PC-KBD: Keyboard data flows to PS/2 connector on desktop system.
- Workstation-PC-KBD: Keyboard data flows to an RS232 Serial connector on a desktop system.
- Workstation-PC-Mouse: Mouse data flows to an RS232 Serial connector on a desktop system.
- Workstation-Generic: Keyboard and Mouse data flows to a PS/2 connector on a desktop "Workstation" system.
- AK125-Mouse: The "raw" PS/2 mouse data from "Mouse IN" exits the breakout box here, and is sent to the keyboard. From there the mouse data either comes back to this connector (for PS/2) or is sent to the AK125-Desk-PC-Workstation connector, changed into a serial protocol.
- AK125 System: +12VDC (and ground) is available from this connector to the keyboard, but other pins are unknown. Most are shared with the HOST-SYSTEM connector, direction unknown.
- HOST-SYSTEM: At least five signals shared with the "AK125 System" connector. TODO: Find out more.
+12VDC
Ground plane
Sun Keyboard and mouse connector
| Pin | Function | Dir'n | Destination | Protocol | Comments |
|---|---|---|---|---|---|
| 4 | (RX/)TX mouse | From | Pin 7 of AK125-Desk-PC-Workstation, inverted | Sun Serial, TTL | TX only |
| Contact | Pin 9 of Workstation-PC-Mouse | Serial | . | ||
| 5 | Kbd RX | To | Pin 3 of AK125-Desk-PC-Workstation | Sun Serial, TTL | . |
| Contact | Pin 8 of Workstation-PC-KBD | Serial | . | ||
| 6 | Kbd TX | From | Pin 2 of AK125-Desk-PC-Workstation, inverted | Sun Serial, TTL | . |
| Contact | Pin 9 of Workstation-PC-KBD | Serial | . | ||
| 8 | Power, +5V | To | Pin 6 of AK125-Desk-PC-Workstation | power | . |
| Contact | Pin 1 or 6?, maybe, of Workstation-Generic, and Pin 1 of Workstation-PC-Mouse, and Pin 1 of Workstation-PC-KBD |
power | TODO: Which pin? |
Goes to Keyboard "HOST"
| Pin | Function | Dir'n | Destination | Protocol | Comments |
|---|---|---|---|---|---|
| 1 | Ground | To | HOST-SYSTEM & Keyboard "HOST" | power | . |
| 4,5,6,9 | Ground | To | HOST-SYSTEM & Keyboard "HOST" | power | . |
| 15 | Ground | To | HOST-SYSTEM & Keyboard "HOST" | power | NOT connected to HOST-SYSTEM connector. |
| 12,13,14 | Power +12V | To | HOST-SYSTEM & Keyboard "HOST" | power | . |
| * * * | |||||
| 2,3 | Unknown | ? | HOST-SYSTEM | other | |
| 7 | Unknown | ? | HOST-SYSTEM | other | |
| 10,11 | Unknown | ? | HOST-SYSTEM | other | |
| * * * | |||||
| 8 | Unused? | ? | (none?) |
Six pins are grounded, three more carry +12VDC power. The remaining six all have unknown functions.
Only 12VDC is ever used to supply the keyboard. None of the pins go anywhere
on the breakout board except to the HOST-SYSTEM & keyboard "HOST"
connectors. Therefore, the ONLY KNOWN use for the host connector for our
application is 12VDC power (and ground) to the kbd.
There are a total of 5 pins of unknown functions that are still to be
determined. Interestingly, 4 come in 2 pairs, on adjacent pins.
TODO: Review, and double check all these. Indicate direction.
Summary: This connector does almost all of the "heavy lifting" for keyboard functions. This connector goes to the "Desk PC/Wkst" connector on the kbd. Given that the other two connectors on the keyboard are only used for mouse functions and power, this is the main connector for keyboard use.
The pins coming from the keyboard, through this connector, end up extending out to two systems, and three protocols:
- Desk-PC (PS/2)
- Workstation-Generic (PS/2)
- Workstation-PC (RS232 Serial)
- Workstation-SUN (Sun Serial)
The Workstation-Generic and Workstation-SUN are connected together. You cannot send to one without sending to the other. This implies that you should connect at most one of these as a workstation, but not both.
| Pin | Function | Dir'n | Destination | Protocol | Comments |
|---|---|---|---|---|---|
| To Workstation-SUN connector | Sun Serial protocol | ||||
| 2 | Kbd TX | To | Pin 6 of Workstation-SUN | Sun Serial | Pink: Signal is inverted between here and Workstation-SUN |
| 3 | Kbd RX | From | Pin 5 of Workstation-SUN | Sun Serial | Yellow |
| 6 | Power +5V | From | Pin 8 of Workstation-SUN | Power | Orange |
| 7 | Mouse TX | To | Pin 4 of Workstation-SUN | Sun Serial | Lt. blue: Signal is inverted between here and Workstation-SUN |
| To Wkst-PC-KBD and Wkst-PC-Mouse connector | Serial protocol | ||||
| 1 | Mouse, UNKNOWN | To? | Pin 8 of Wkst-PC-Mouse | Serial | Brown: TODO: double check. Used for kbd to sense presence of Wkst mouse? |
| 2 | Kbd TX | To | Pin 9 of Wkst-PC-KBD | Serial | Pink |
| 3 | Kbd RX | From | Pin 8 of Wkst-PC-KBD | Serial | Yellow |
| 6 | Power +5V | Contact | Pin 1 of Wkst-PC-KBD & Pin 1 of Wkst-PC-Mouse |
Power | Orange |
| 7 | Mouse TX | To | Pin 9 of Wkst-PC-Mouse | Serial | Lt. blue |
| To Wkst-Generic | PS/2 protocol | ||||
| 4 | Kbd Data(?) | To | Pin maybe 8 or 9 of Wkst-Generic | PS/2 | White: TODO: Test to determine right pin # |
| 5 | Kbd Clock(?) | To | Pin maybe 9 or 8 of Wkst-Generic | PS/2 | Black: TODO: Test to determine right pin # |
| 6 | Power +5V | Contact | Pin 6? of Wkst-Generic | Power | Orange |
| To Desk-PC-KBD | PS/2 protocol | ||||
| 8 | Kbd Data | To | Pin 8 of Desk-PC-KBD | PS/2 | green |
| 9 | Kbd Clock | To | Pin 9 of Desk-PC-KBD | PS/2 | purple |
Results:
One set of kbd data and clock using PS/2 protocol. (Pins 8, and 9 of
this connector going to pins 8 and 9 of Desk PC Kbd.) The only thing we
have working so far.
2 Sun signals, TX and Mouse(TX), inverted as they go to the Sun keyboard connector.
1 Sun signal, RX, NOT inverted as it comes from the Sun keyboard connector.
1 Sun +5VDC. TODO: MAYBE THIS IS USED TO DETECT ANY WKST IS PRESENT?
The "Sun Kbd TX signal" also goes to Wkst-PC-KBD pin 9, not inverted
(serial)
The Sun TX Mouse signal also goes to Workstation-PC-Mouse, pin 9
One set of 2 pins (Serial protocol), pins 1, 7 go to
Workstation-PC-Mouse, Pin 8, 9
One set of 2 pins (PS/2), 4 and 5 go to Workstation-Generic, Pin 8?, 9?
(8 = Sun +5VDC. 9 = Sun mouse TX)
Pins are PS/2 connector pins, not PCB order.
From connector to Breakout Box:
| Pin | Function | Dir'n | Destination | Protocol | Comments |
|---|---|---|---|---|---|
| 1 | Mouse data | To | Pin 3 of AK125-Mouse | PS/2 | |
| 5 | Mouse Clock | To | Pin 2 of AK125-Mouse | PS/2 |
From connector to mouse:
| Pin | Function | Dir'n | Destination | Protocol | Comments |
|---|---|---|---|---|---|
| 1 | Mouse data | From mouse | PS/2 | ||
| 3 | Ground | To mouse | Power | ||
| 4 | +5VDC | To mouse | Power | ||
| 5 | Mouse Clock | From mouse | PS/2 |
The AK125-Mouse connector receives a PS/2 mouse signal from the Brekout box "Mouse IN" connextor. The keboard logic then figures out where the mouse output needs to be directed (which of the four sets of ports) and sends the needed signals:
- back out the AK125-Mouse connector on the Breakout box for the PS/2 signals: Desk-PC-Mouse and Workstation-Generic, or
- out to the AK125-Desk-PC-Workstation for the RS232 and Sun serial signals: Workstation-Sun and Workstation-PC-Mouse.
All 9 pins are used.
| Pin | Function | Dir'n | Destination | Protocol | Comments |
|---|---|---|---|---|---|
| 1 | ?? | ?? | Pin 1 of Desk-PC-Mouse and Pin 1 of the Desk-PC-KBD |
?? | TODO: PURPOSE? Perhaps to detect power from Desk system? |
| 2 | Mouse Clock | From | Pin 5 of Mouse-IN | PS/2 | |
| 3 | Mouse data | From | Pin 1 of Mouse-IN | PS/2 | |
| 4? | To | Pin 5 of Wkst Generic | √ light blue | ||
| 5? | Mouse data? | To | Pin 8 of Desk-PC-Mouse | √ pink: | |
| 6? | Mouse Clock? | To | Pin 6? of Desk-PC-Mouse | √ white | |
| 7 | To | Pin 4 of Wkst-Generic | √ brown | ||
| 8 | To | Pin 3 of Wkst-Generic | √ purple/dk blue | ||
| 9 | To | Pin 2 of Wkst-Generic | √ grey |
Results:
Mouse data & clock to: Desk-PC-Mouse
4 signals to Wkst-Generic. Mouse clock and data plus 2 more: UNKNOWN
Pin 1 goes to Pin 1 of Desk-PC-Mouse and Desk-PC-KBD. Purpose: UNKNOWN
| Pin | Function | Dir'n | Destination | Protocol | Comments |
|---|---|---|---|---|---|
| 1 | ?? | ?? | Pin 1 of AK125-Mouse | ?? | Unknown use/signal. Power? |
| 6 | Mouse Clock? | From | Pin 6? of AK125-Mouse | PS/2 | |
| 8 | Mouse Data? | From | Pin 5? of AK125-Mouse | PS/2 |
Results: Likely Desk PC will output PS/2 mouse info to here. Untested.
| Pin | Function | Dir'n | Destination | Protocol | Comments |
|---|---|---|---|---|---|
| 1 | ?? | ?? | Pin 1 of AK125-Mouse and Pin 1 of Desk-PC-KBD |
?? | Unknown use/signal. Power? |
| 8 | Kbd Data | From | Pin 8 of AK125-Desk-PC-Workstation | PS/2 | |
| 9 | Kbd Clock | From | Pin 9 of AK125-Desk-PC-Workstation | PS/2 |
Results: This is PS/2 keyboard protocol, known to work.
RS232 Serial protocol.
| Pin | Function | Dir'n | Destination | Protocol | Comments |
|---|---|---|---|---|---|
| 1 | Sun +5V power | ?? | Pin 6 of AK125-Desk-PC-Workstation and others |
Power | Power, possibly used to check for presence of any workstation? |
| 8 | Kbd RX | From | Pin 3 of AK125-Desk-PC-Workstation | Serial | |
| 9 | Kbd TX | From | Pin 2 of AK125-Desk-PC-Workstation | Serial |
Results: This is a keyboard (not mouse) RS232 Serial protocol port coming through a DB9. Pick this OR the Sun Din8, not both.
RS232 Serial protocol.
| Pin | Function | Dir'n | Destination | Protocol | Comments |
|---|---|---|---|---|---|
| 1 | Sun +5V power | ?? | Pin 6 of AK125-Desk-PC-Workstation and others |
Power | Power, possibly used to check for presence of any workstation? |
| 8 | UNKNOWN | ?? | Pin 1 of AK125-Desk-PC-Workstation | Serial? | Blue line on cover |
| 9 | Mouse TX | From | Pin 7 of AK125-Desk-PC-Workstation | Serial |
Results: This is a mouse (not keyboard) RS232 Serial protocol port coming through a DB9. Pick this OR the Sun Din8, not both.
PS/2 protocol (Data and Clock)
TODO: It's quite hard to map the pins going into this connector. Waiting for more info.
| Pin | Function | Dir'n | Destination | Protocol | Comments |
|---|---|---|---|---|---|
| 6 or 1? | Sun +5V power | ?? | Pin 6 of AK125-Desk-PC-Workstation and others |
Power | Power, possibly used to check for presence of any workstation? |
| 2 | UNKNOWN | ?? | Pin 9 of AK125-Mouse | PS/2 | Gray |
| 3 | UNKNOWN | ?? | Pin 8 of AK125-Mouse | PS/2 | Blue |
| 4 | UNKNOWN | ?? | Pin 9 of AK125-Mouse | PS/2 | Brown |
| 5 | UNKNOWN | ?? | Pin 8 of AK125-Mouse | PS/2 | Lt. Blue |
| 7 | (none?) | ?? | | ? | | | 8? | UNKNOWN | ?? | Pin 8 of AK125-Desk-PC-Workstation| ? | White? | | 9? | UNKNOWN | From| Pin 4 of AK125-Desk-PC-Workstation| ? | Black? |
Two mouse pins
Two Kbd pins
+5VDC if Sun keyboard is connected to Workstation-Sun
TODO: Mostly a pass through from the AK125 System connector.
| Pin | Function | Dir'n | Destination | Protocol | Comments |
|---|---|---|---|---|---|
| 1 | Ground | To | HOST-SYSTEM & Keyboard "HOST" | power | . |
| 4,5,6,9 | Ground | To | HOST-SYSTEM & Keyboard "HOST" | power | . |
| 15 | NOT connected | To | HOST-SYSTEM & Keyboard "HOST" | N/C | |
| 12,13,14 | Power +12V | To | HOST-SYSTEM & Keyboard "HOST" | power | . |
| * * * | |||||
| 2,3 | Unknown | ? | AK125 System | other | |
| 7 | Unknown | ? | AK125 System | other | |
| 10,11 | Unknown | ? | AK125 System | other | |
| * * * | |||||
| 8 | Unused? | ? | (none?) |