consul-vdx-term-keyboard-converter/README.md

# Keyboard Converter: Consul 262.5 & VDX 52600

![Terminal with keyboard and the converter](overview.jpg)

Arduino project for a keyboard converter between a Zbrojovka Consul 262.5 terminal keyboard and a Videoton VDX 52600 terminal.


## Keyboard: Consul 262.5

Terminal keyboard from 1980s.
It uses a DB25 connector with UART TTL data lines, clock line, +5V primary power and -12V auxiliary power.

## Terminal: VDX 52600

VT52 termnial with a DIN5 keyboard connector that dones not use the standard AT keyboard protocol.


## Converter

Interfaces the keyboard and the terminal, optionally a USB. These modes of operation are supported:

1. Keyboard and terminal connected: primary standalone mode. Everything is powered from the terminal.
2. Keyboard and USB connected: USB keyboard mode. Powered from the USB which acts as a HID keyboard.
3. Terminal and USB connected: Serial keyboard over USB mode. Powered independently. Allows sending keystrokes to the terminal over USB serial.

![Converter box](box.jpg)


## Parts needed

- Arduino Leonardo
- Symmetrical boost converter, 5V to +/- 12V
- Piezo speaker
- red and green LED + 470 ohm resistors
- connectors
- project box 
- (among others)


## Connections

### Terminal DIN5

Device | Controller | Description
---|---|---
GND | GND | Ground
+5V | +5V | Power
Data | 6 | Keyboard data to terminal
Status | 7 | Status (LEDs) and Clock from terminal

![DIN5 connector pinout](DIN5_pinout.jpg)


### Keyboard DB25

Device | Controller | Description
---|---|---
GND | GND | Ground
+5V | +5V | Power
-12V | -12V | via a symmetrical boost converter
Serial out | 3 | UART out from keyboard
Serial in | 4 | UART in to keyboard


### Box Interface

| Controller | Description |
| ---|--- |
| 10 | Offline LED |
| 9 | Online LED |
| 8 | Speaker |


### Terminal DB25

The VDX 52600 terminal uses the standard DB25 serial connector to connect to an RS-232 serial link. It is enough to connect pins (2) TX, (3) RX and (7) GND.
See [RS-232 over DB25 connector](http://www.nullmodem.com/DB-25.htm) for more.

By default the serial port configuration is 9600–8-N-1 (i.e. the standard baud rate of 9600). Connecting it to a serial port of a Linux machine works nicely.