Simple USB - ICOM bus interface, SM7LCB

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. 

TOP


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.

TOP


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.


TOP



SM7LCB
End of this page
Document made with Nvu