HW_ED1000 - fablab-wue/piTelex GitHub Wiki
Electronic for ED1000 Interface
TODO
In frequency domain ...
When sending a character the transmitter switches between the corresponding frequencies with the given baud rate.
In the old days a lot of electronic components were required to build a modulator and demodulator for Frequency Shift Keying (FSK). Today most of the work is done by software.
For our project, we use a (USB) sound card to play and record the carrier frequencies, and just 5 electronic components adapt the audio signal to the teletype ED1000 specifications.
With this USB sound card adapter the teletype can be connected to a Windows-PC, a Linux-PC, a Mac (not tested) or a Raspberry Pi (not tested). For Raspberries, a USB sound card is needed and available in online shops for about 10€. With PC or Laptops, their built-in sound card is equally suitable.
Connecting a PC Sound Card to ADo8
ADo8 Plug
Pin | Description |
---|---|
1 | Line a |
2 | nc |
3 | nc |
4 | Line b |
5 | Bridge to 6 |
6 | Bridge to 5 |
7 | nc / Option: Paper-End-Switch |
8 | nc / Option: 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. Caution: Some teletypes apply high voltages here!
Some teletypes use a switch (relay) on pin 7 and 8 to indicate "end of paper".