Exactly. The transistor provides both the level shift and invert functions, so just connect it between the rig (TTL) and serial port (RS-232).
Greg. KO6TH
On March 24, 2015 5:47:19 AM PST, Daniel Cussen dan@post.com wrote:
On 24/03/2015, Andre sats@pe1rdw.demon.nl wrote:
If fyou are going to homebuild you can skip the whole level shifter
and
inverter. Just get a usb to ttl cable an attacht the needed connector to the
open
end of the cable.
Just be aware, as already said the signal is INVERTED so a 1 is a 0 and a 0 is a 1, so the logic level needs to be the opposite of normal RS232 TTL levels, so connecting a standard 5V TTL to a connector probably will not work with a circuit to invert the logic. _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb