Example_SEU M_LO2000

Example with SEU-M-board with Raspberry Pi inside a LO2000, LO2001 or LO3000

SEU-M-board

For details of the SEU-M-board see MicroTelex-wiki

LO2000 and SEU-B-card

Research has shown that the SEU-B cards (ED1000, Germany) as well as the SES-B cards (V.21, Austria) communicate with RS232 levels (+/-12V). Also implemented in the LO2000, LO2001, LO3000, T1000S. So it makes sense to talk directly to the teletype without going through a SEU or SES card. This was also successfully possible with a USB serial adapter.

The protocol used corresponds to that of the ED1000 standard:

• TXD High with pulses: write mode / communication
• TXD permanently low: sleep mode, engine off
• RXD permanently LOW: FS in sleep mode
• RXD High: FS wants to dial (Exact procedure see i-Telex-Wiki - ED1000)

If you are in the process of laying out a board anyway, it makes sense to provide the drivers for RS232 right away. In this way, the SEU-M card can be plugged directly into the LO2000 with an alternative configuration (telex.json) instead of a classic SEU card.

Depending on the Raspberry Pi used, the network connection is via WLAN or Ethernet.

With SEU-M-board

Simply insert the SEU-M card with a Raspberry Pi (Zero (W), 1B, 2B 3) and piTelex image into the teletype and you already have a cheap alternative to participate in the i-Telex network.

The user in front of the FS will not notice any difference whether the LO2000 is operated with i-Telex or piTelex or with the SEU-M card inserted.

The SEU-M card and the Raspberry are supplied with power via the LO2000.

Connector SEU-B-card

The LO2000 and the SEU/SES-cards uses a connector with name "DIN41617".

LO2000 has a 31-pin female connector. The SEU/SES-cards has an 21-pin male connector with common pin 1.

For this project a 13-pol male connection (starting at pin 9) provides all necessary signal for controlling the LO2000.

Pin	SEU Name	Comment
2	a	connected to ADo8-cable pin 4, routed over filter-card
3	b	connected to ADo8-cable pin 1, routed over filter-card
4	T0	GND
7	MP-osc	Measurement point oscillator
9	+T	+12V
10	STÜ, LÜ	Check for plug is in wall outlet, pullup to 12V
11	-T	-12V
12	Dab	AGT_RX - from teletype to SEU-B-card (RS232 level)
13	LS	nc, used by TW39-card
14	LP	nc, used by TW39-card
15	Dan	AGT_TX - from SEU-B-card to teletype (RS232 level)
16	MP-dis	Measurement point discriminator
17	+B	+12V
18	-B	nc, (-12V)
19	B0	GND
20	2DRE	nc, used by TW39-card
22	0V~	nc, 60V AC (LO2000, not part off SEU-B-card)
23	60V~	nc, 60V AC (LO2000, not part off SEU-B-card)

Additional on SEU-M-board

Additional to the SEU-B pinout internal signals are available on the 31-pin connector.

The pins above 21 are used on the SEU-M-board to provide additional signals (VDD, 5V, I2C, power relay, aus relay).

Pin	Name	Comment
24	I2C SCL
25	I2C SDA
26	+5V	5V out
27	GND
28	VDD	12V out
29	AUX-Relay	for extern relay/SSR connected to +5V or VDD
30	POW-Relay	for extern relay/SSR connected to +5V or VDD
31	9...24V	Input for DC/DC converter (typical in Ö-AGT)

50, 75 or 100 Baud

With the SEU-M card as a controller, the LO2000 can also be operated with 75 or 100 baud. In the LO2000, only the DIP switch (light blue) on the LP9 needs to be changed (both switches for 100Bd).

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Software

See TW39 Raspberry Pi

Configuration (telex.json)

    # Lorenz LO2000 or LO2001 (or LO3000) with a SEU-M-card INSIDE as controller
    # Note: SEU-M-card (with aRPi) is a replacement of a SEU-B ord SES-B-card
    "RPiTTY_SEU-M_LO2000": {
      "type": "RPiTTY",
      "enable": false,
      "mode": "TWM",
      "pin_txd": 17,
      "pin_rxd": 27,
      "pin_relay": 22,
      "inv_relay": false,
      "pin_power": 0,
      "inv_power": false,
      "pin_number_switch": 0,
      "baudrate": 50,   # 50, 75, 100
      "coding": 0,   # 0=ITA2
      "loopback": false
    },