Echolink interface (UK)

After weeks of collecting parts and one Sunday of soldering, drilling and sawing it was ready to go: the echolink interface. The device has been built with the PH0DV┬áinterface as an example. Except that I wanted to save USB ports at the Raspberry Pi and avoid a hassle with different cables. Therefore I’ve included a USB hub in the same housing. A piece of universal PCB is the base, containing a USB-B socket, the 1:1 transformers and an optocoupler to switch PTT.

I’ve removed the USB-A connector from the hub and replaced it by some ribbon cable connected to the USB-B connector.

The picture of the opened interface shows in the left upper corner the USB-B connector. To its right the USB hub has been mounted. Connected to the USB hub are a USB soundcard (green PCB) and a CP2101 level converter. The USB soundcard is the cheapest one which can be bought online. The housing of the soundcard has been removed to reach the soldering side of the PCB. With short wires the soundcard has been connected to the 1:1 transformers. The light blue housing at the picture comes from the sound device, but has been misused as it has been glued to the bottom of the metal case to keep the PCB tightly at its place.

The second module connected to the hub is the CP2101 level converter. Only the DTR and ground pin are used. The DTR pin has been connected via a red led and a resistor to the optocoupler to switch PTT.

Furthermore the front panel contains a 5mm led in a neoprene socket. Below the led the male DB- socket to connect the transceiver is visible. To be sure that after months or years it’s still clear how to connect to this interface, the pinout of the DB9 has been printed to a label at the bottom of the housing.