Quantity   Component name
1 × Arduino Mega 2560 R3
1 × 4x4 keypad with matrix encoding for hexadecimal input
1 × 3x4 telephone keypad, for function buttons and DIN input, NOT matrix encoded
8 × LEDs and matching protection resistors (for 5 V)
4 × Pull-down resistors for DIN digital inputs (typical 10 kOhms)
4 × Standard signal diodes for digital outputs to prevent leakage currents from external electronic circuits
8 × N.O. momentary push buttons
1 × Power Switch
2 × Adafruit 7Segment LED backpacks
1 × Potentiometer, 100 Ohms for LCD Contrast
1 × Potentiometer, 200 Ohms for CPU Throttle
1 × 4x20 LCD display, standard Hitachi HD44780
1 × Laser-cut face plate (see blueprint in files here)
1 × Ethernet + SDCard shield (optional)
1 × Emic 2 TTS Module / Speech Synthesizer (optional)
1 × Wires, wood, hinges, hot glue, solder, tools, ...