P_ED1000
FOR FUTURE PLUGINS - NOT IMPLEMENTED YET
ED1000 is a technique to connect a teletype to a central office with 2 wires. A Frequency-Shift-Keying (FSK) is used to send and receive simultaniously. It is like a MODEM (V.21) but with different carrier frequencies.
| Type | Definition |
|---|---|
| A | Central Office, Switching Exchange, EDS, (PC Sound Card) |
| B | Terminal Station, Teletype |
Type 'B' is the normal configuration for a teletype. Some teletypes can be configured as type 'A' to be connected directly to another teletype.
| SEU | Direction | Frq A (space, 0) |
Frq Z (mark, 1) |
Level | U rms * | U peak * |
|---|---|---|---|---|---|---|
| A | Send | 500Hz | 700Hz | -14.5dBm | 0.146V | 0.206V |
| A | Receive | 2250Hz | 3150Hz | ≥-34.0dBm | ≥0.015V | ≥0.022V |
| B | Send | 2250Hz | 3150Hz | -9.0dBm | 0.275V | 0.389V |
| B | Receive | 500Hz | 700Hz | ≥-28.5dBm | ≥0.029V | ≥0.041V |
*: at termination of 600Ohm
Seeing the lower frequencies as a bit value '0' and the higher as '1', the bit values can be used as from a TTL async. serial adapter.
| Distance | Conductor Diameter |
|---|---|
| 20km | 0.8mm |
| 14km | 0.6mm |
| 10km | 0.4mm |
| Direction | Frequency Band | Loss |
|---|---|---|
| A → B | 600Hz ± 100Hz | 14dB |
| B → A | 2700Hz ± 450Hz | 25dB |
It is common for ED1000 system to use an ADo8 plug.
| Pin | Description |
|---|---|
| 1 | Line a |
| 2 | nc |
| 3 | nc |
| 4 | Line b |
| 5 | Bridge to 6 |
| 6 | Bridge to 5 |
| 7 | nc / Paper-End-Switch |
| 8 | nc / Paper-End-Switch |
The line wires are used to send and receive at the same time like a MODEM on phone wires.
The bridge between pin 5 and 6 is for signaling a connected plug. May be high voltages can be used by teletype to detect the bridge!
Some teletypes use a switch (relay) on pin 7 and 8 to signal paper end.
For signaling Z (logical 1) a high frequency is used (700Hz, 3150Hz). For signaling A (logical 0) a lower frequency is used (500Hz, 2250Hz). Both frequencies have the same amplitude.
In frequency domain ...
For sending a character the transmitter switches between the corresponding frequency with the giver baud rate.
For timing see: Baudot-Murray-Code
Idle mode ...
Pressing button AT on FSG...
On fail...
On success...
Typing characters...
Transmitting without pause...
Pressing button ST...
Ending by other side...
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Local use
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i-Telex
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Advanced Topics
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Tools & Gadgets
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TW39 (current loop)
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ED1000 (FSK modulation)
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V.10 (TeKaDe FS200, FS220)
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SEU-M-board based
- with Austrian AGT (Ö-AGT, current loop)
- as replacement for SEU-B card inside LO2000, LO2001, LO3000