[amsat-bb] FT736R cable
sats at pe1rdw.demon.nl
Tue Mar 24 11:24:10 UTC 2015
If fyou are going to homebuild you can skip the whole level shifter and
Just get a usb to ttl cable an attacht the needed connector to the open
end of the cable.
73 de Andre PE1RDW
Op 24-03-15 om 06:12 schreef Greg D:
> The FT-736R definitely has a serial interface, but it's not USB. It's
> the old style serial, aka "RS-232" or "Com port", except the signal
> levels are TTL (0-5v) instead of proper RS-232 (-12 to +12 usually).
> Actually it's +12 to -12, i.e. inverted in sense compared to TTL. So
> one needs a level shift and invert, which is what the circuit is for,
> and that then needs to plug into a Serial port.
> Most computers built in the last several years (decade?) don't have
> serial ports, having replaced them for peripheral attachments with USB
> ports. Some computers have more USB ports than my car has cup holders.
> The difference is protocol - what information gets sent over the wires -
> and there USB is very different than simple Serial. If your computer
> doesn't have a serial port, you need to buy a USB to Serial adapter, and
> then plug the referenced circuit into that.
> What Daniel refers to on sites like eBay are essentially the combination
> the two parts. They have a USB to RS-232 adapter, and the level
> shifter/inverter, all in one package. Good deal if you don't feel like
> a soldering project, but, yes, watch out for the drivers.
> Regarding the circuit, if your program only sends commands to the 736,
> and never reads information from the 736 (I don't know of any that do),
> then you can simplify the diagram to just R1 and Q1. Either way, I would
> recommend you add a small diode (1N4001 or 1N914) between the Base of Q1
> and ground (the Emitter pin), cathode at the Base, to protect Q1 from
> the negative swing of the RS-232 signal.
> Good luck!
> Greg KO6TH
> Daniel Cussen wrote:
>> Here is the wiring of a serial interface
>> For usb to TTL you need 5V TTL logic and presumably similar
>> connections and baud rates.
>> If you look on ebay you can see people selling them and the rig end
>> needs the right connector, a 6 pin DIN.
>> You connect the TX of the USB lead to the RX on the radio (pin3) and
>> the output of the rig (pin 2) to the RX on the USB converter and pin 1
>> to ground.
>> You probably don't need the pin 6 connection as the converter will be
>> supplied by the USB power.
>> Make sure to get a USB cable with drivers available for your current
>> operating system and ideally a common one so that drivers will be
>> available in many years time for future systems.
>> Ideally if you could afford it a fully isolated interface would be
>> On 23/03/2015, ingejack at cox.net <ingejack at cox.net> wrote:
>>> Need to know what USB cable that FT736R users are using to connect
>>> computer and SATPC32 with. It calls for a RS232 TTL cable but need to
>>> what company and cable descrition they are using if possible., Thanks
>>> any help !! Jack/KC7MG
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