| Last updated 15 June 2009. | Back SM7LCB remote page |
Presentation
On my ICOM bus interface page I show a simple interface between a standard COM-port and the ICOM bus made by Bill, G3MCS. But the normal COM-port is today not so common on new computers and you need to get an USB to COM-port adapter to use the simple interface made by Bill. But I will here show a very simple USB to ICOM bus interface which is very easy to build.
This interface use a ready made USB to serial cable from the company FTDI. There main product chips for USB to COM-port and also USB to LTP-port. But they also sell the TTL-232R cable which easy can be used to build this interface.
- For more information about FTDI see there home page.
- For the TTL-232R I have here a PDF document about this cable.
Schematic
Below is the simple schematic of this interface!
- The FTDI TTL-232R 5V version can be find at ELFA. Note that it shall be the 5V version (there is a 3.3V also).
- The red wire support +5V from the USB and is used to pull-up the ICOM-bus.
- The yellow (TxD) and Orange (RxD) is the serial data from USB with TTL levels (same as for ICOM-bus).
- The black wire is 0V.
- The zener diode is a small ESD protecting but not needed.
Building
It is easy to build. I build it in a small box with two BNC connectors for the ICOM bus connection. Maybe you want other connector.
The picture below show the internal wiring.
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