Example_V10RPiV2

Example with V.10 at Raspberry Pi V2

For this design a PCB was made.

Main features:

• correct V.10 voltage level
• wired-or (2 diodes and resistor) for printing own typed characters in red and incoming characters in black
• reconfigurable (solder pads) for V.24 with TXD, RXD, RTS, CTS

Additional (optiona) features:

• I2C connector
• NeoPixel connector
• 1 user-button connector (medium cable length)
• off-button connector (short cable length)
• duo-color-LED to show the connection status
• SSR connector for power saving

Hardware

All you need is a Raspberry Pi, a MAX232 as driver and a hand full of resistors, capacitors and diodes.

Schematics

See PDF-file: https://github.com/fablab-wue/piTelex.supplement/blob/master/PCB_KiCad/piTelex_V10_1.0.0/PDF/piTelex_V10_1.0.0.pdf

This design is based on MAX232 chip to support the full V.10 specification (without negative voltage hack).

For more electronic details see Electronic for V.10.

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Connectors

J6 - V.10 (V.24) to teletype

Pin	Name	Pin DSub	V.10 Name	Comment
1	GND	7 + 9 + 11	E1, E21, E22
2	+5V	-	-	not used
3	RXD	2	D1	from teletype to RPi
4	TXD	3	D2	from RPi to teletype
5	CTS	4	S2	status/observe line. Goes to high if teletype is in LIN-mode
6	RTS	-	-	not used

Software

For piTelex installation see SW_Install

This adapter is handled by the software module RPiTTY.

The settings in the file telex.json have to be adapted:

...
    # TeKaDe FS200 or FS220 over V.10 interface (new pinout)
    "RPiTTY_FS200_V10_new": {
      "type": "RPiTTY",
      "enable": true,
      "mode": "V10",
      "pin_txd": 27,               # Pin13
      "pin_rxd": 17,               # Pin11
      "pin_relay": 0,
      "inv_relay": true,
      "pin_power": 9,              # Pin21
      "inv_power": false,
      "use_observe_line": true,
      "pin_observe_line": 22,      # Pin15
      "inv_observe_line": true,
      "nZZ_observe_line": true,
      "baudrate": 200,             # 50, 75, 100, 200
      "coding": 0,                 # 0=ITA2
      "loopback": false
    },
...

Note: To use the i-Telex communication module, enable and configure the i-Telex section in telex.json.

Start the program telex.py with no arguments on RPi-Linux:

./telex.py