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+# 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
+
+*TODO*
+
+
+### Terminal DIN5
+
+Device | Controller | Description
+GND | GND | Ground
++5V | +5V | Power
+Data | 6 | Keyboard data to terminal
+Status | 7 | Status (LEDs) from terminal
+
+### 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
+