On Mon, 24 Jan 2005 03:38:39 -0500, starman wrote:



Soliloquy wrote:

PLEASE READ. Computers uses RS-232 signal levels and protocol when you
connect to the serial port. The FRG-100 Requires TTL levels to connect to
it, therefore signal conversions need to take place between the computer
and radio.

DO NOT CONNECT your FRG-100 directly to the serial port, use a compatible
converter, like the Yaesu CT-62 for the FRG-100.

That's strange. Why would they not have designed it with an RS-232
interface?
Because RS-232 levels require voltages that are rarely seen on
transistorized equipment these days. Just about everything except
RS232 run on 3.3 or 5 volts. RS232 levels are + and - 10 volts or so,
and 20ma current loop is often about 100 volts!

Chips like the Max232 exist to deal with precisely this problem...