https://github.com/thotypous/telecom-p2-board

E1/T1 interface board for Tang Nano 9k
https://github.com/thotypous/telecom-p2-board

Last synced: about 1 month ago
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E1/T1 interface board for Tang Nano 9k

• Host: GitHub
• URL: https://github.com/thotypous/telecom-p2-board
• Owner: thotypous
• License: mit
• Created: 2024-08-01T19:08:07.000Z (5 months ago)
• Default Branch: main
• Last Pushed: 2024-08-02T01:14:18.000Z (5 months ago)
• Last Synced: 2024-08-03T02:02:34.428Z (5 months ago)
• Homepage:
• Size: 6.71 MB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# E1/T1 interface board for Tang Nano 9k

This is a simple adapter for connecting a FPGA board to an E1/T1 interface via short distance twisted pair.

RX is done by a couple of comparators (KA319 or LM319) which detect, respectively, positive (`RXP_N` low) and negative (`RXN_N` low) pulses.

TX is done directly by the FPGA pins. Current flows either from `TXP` to `TXN` to produce a positive pulse, or from `TXN` to `TXP` to produce a negative pulse.

The FPGA design is one of the exercises of the [Communications Technology class](https://telecom.matias.co.in) at [UFSCar](https://ufscar.br). Starter files and a guide for developing the project can be found [here](https://github.com/thotypous/telecom-p2).

## Schematics

Schematics are available both in [PDF](board/board.pdf) and in [Kicad format](board/board.kicad_sch).

## PCB

We don't have a proper PCB layout. Please feel free to contribute one.

Instead, please see below some photos of our milled by hand prototype board.

![](photos/prototype01.jpg)

![](photos/prototype02.jpg)

Please note that although one should ideally use 1:1 transformers, we only had at hand a couple of security camera baluns (designed to work as 75 ohm to 100 ohm impedance transformers), which worked just fine.