Keyboard --> RJ-11

In git.unix.linux Luke Albers wrote: | 1) Rxd (Data to keyboard)

| 2) Gnd

| 3) +12v

| 4) Txd (Data from keyboard)

| Here is a link to the pinouts of the kbd connectors:

It should be fairly intuitive but your keyboard will not work with this terminal. PS/2 keyboards run on 5 volts and your terminal is supplying 12 meaning you'll burn out the keyboard the moment you plug it in.

Keeping this in mind, the signal level requirements may be different between the devices. The PS/2 keyboard uses TTL level signals (0 and 5 volts). It looks like the terminal may use stanard serial level comms which is something completely different.

You could build an interface provided both units are speaking the same protocols. In that case, you'd have to make an opto-isolator circuit plus a voltage regulator to reduce the 12 volts to 5 for the keyboard. Your pin 4 is receiving data so it would go to pin 2 on the AT connector and the transmitting pin is pin 1 which the closest analogue on the AT connector is the clock.

This is where things get different. The PS/2 and AT keyboards use a synchronous serial connection. The computer clocks the keyboard and the keyboard shifts data out the data pin. But, at the same time, the keyboard can _read_ data from the data pin which the computer sent to it. So, the data pin is actually bi-directional. The clock is just a clock. However, it looks like the terminal's keyboard is a real serial device which follows along with the rest of the terminal since it's an all serial device. It's more than likely receiving commands or a pulse stream on the receive pin and transmits data on the transmit pin. So there's no bidirectional communication over a single wire like the PS/2 keyboard.

Don't bother. It is higly unlikely the protocol is PS/2.

Just because the terminal has a modular connector does NOT mean that a standard PC keyboard will work with it. In fact, it is not at all common for dumb terminals to have the same keyboard protocol and interface as a PC.

You need to check with the terminal manufacturer, otherwise you run a very high risk of blowing a circuit or three.

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"Luke Albers" schreef in bericht news:bq6ial$9qo$ snipped-for-privacy@news-int2.gatech.edu...

would

Well Luke,

A PC/AT/ps2 keyboard eats 5V. You will sure blow it when you feed it 12.

You did not tell what type of terminal you got. Most of the ones I know used a kind of ASCII on a serial connection. If you still have the keyboard, you best use it. If that's not an option (p.e. due to mechanical ruins) you may nevertheless check the signals with a scope and build a converter. Which requires a voltage regulator and a microcontroller..... You'd prefer a type with a UART inside.

petrus

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Ok I think that my friend gave me the wrong pin diagram. The terminal is an IBM 3153. I found another diagram that showed 5 pins, and it ran off 5 V, and there was only one wire for data. I will have to find the link again, but I think that my RJ-11 connectors only have 4 conductors (i hear some have 6 and are still called RJ11). I will post the pinout that I found ASAP

RJ11 Plug Pin Assignments 1 = KBD Clock 2 = KBD Data +-----------+ 3 = No Connection |1 2 3 4 5 6| 4 = Signal Ground |. . . . . .| 5 = +5 Volts +---+---+---+ 6 = No Connection |___| View = looking at plug.

OK I think that this is something that I can work with. Anyone know how I could connect an AT keyboard?

In that case, you COULD connect the PS/2 data and clock signals to the clock and data signals of the tremina, not saying it will work though.

"Luke Albers" schreef in bericht news: snipped-for-privacy@posting.google.com...

Luke,

You find the pinouts of an AT keyboard below. FAIK the XT keyboard had the same 5 pin DIN connector and the same pinout but a different protocol. The XT also used the reset pin, the AT did not. I still have an XT keyboard equiped the modulair connector you mentioned but I did not check the pinout.

BTW The RJxx notation comes from the telco environment. It has to do with pin identities and functions, not with pin positions or contact count. Outside this specific environment, the RJxx notation is meaningless and gives a lot of confusion.

IBM AT 101 KEY (ENHANCED) KEYBOARD 5 PIN DIN CONNECTOR

Male End PIN SIGNAL Female End 1 ---------------------------------- KBDCLK (clock) 1 3 2 ---------------------------------- KBDAT (data)

3 1 4 5 3 ---------------------------------- KBRST (reset,not used) 5 4 2 4 ---------------------------------- GND 2 5 ---------------------------------- VCC (+5V)

IBM PS/2 KEYBOARD 6 PIN MINI-DIN CONNECTOR Male End PIN SIGNAL

5 H 6 1 -------------------------------- KBDAT (data) 3 4 2 -------------------------------- not used 1 2 3 -------------------------------- GND 4 -------------------------------- VCC (+5v) 5 -------------------------------- KBCLK (clock) 6 -------------------------------- not used

petrus

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If it's something well-known like a DEC or IBM terminal, it might be worthwhile to look on ebay for a matching keyboard.

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