USB to RS232 breakout module???

[AA7EJ]

http://www.ebay.com/itm/USB-to-RS232...item1e60d14133

On ebay - where else.

What is it?
There are only 4 I/O and two of them are power. That is not RS232 breakout.
USB to TX /RX looks more like USB to Bluetooth and the price tag would support it.
Where is the antenna?
I did ask the seller and got no reply.

73 Vaclav

[WA6TKD]

http://www.ebay.com/itm/USB-to-RS232...item1e60d14133

On ebay - where else.

What is it?
There are only 4 I/O and two of them are power. That is not RS232 breakout.
USB to TX /RX looks more like USB to Bluetooth and the price tag would support it.
Where is the antenna?
I did ask the seller and got no reply.

73 Vaclav

Yes, the title is technically incorrect. It is a USB serial converer module, but not a RS-232 type. When plugged into a PC it will become a COM port avalible to any PC application program that can work with serial ports. However it's not a true RS232 convertor as it doesn't interface with device that utilize RS-232 voltage levels. The correct title might be called a USB TTL serial converter module, as the send and receive data lines work at the 0 to +5vdc levels that many devices now use rather then the older RS-232 voltage levels.

I've bought similar devices as this on E-bay to interface some of my Arduino microcontroller devices and they work fine for the function they were designed for. And no, it's not any form of a wireless device.

[AA7EJ]

I can see the USB to level conversion function. The FT 857 CAT cable needs that.
But where did they come up with the TX/RX? That is Bluetooth terminology.
And it really does not tell me how it works.
But for $6 I would play with it.

So if you used it - is it really a parallel ( RS232 byte ) to serial (RX) and serial (TX) to parallel (RS232) converter via USB / COM harware?
Too bad I cannot read the chip label.
May be usefull for some simple control application.
Thanks
73 Vaclav

[WA6TKD]

I can see the USB to level conversion function. The FT 857 CAT cable needs that.
But where did they come up with the TX/RX? That is Bluetooth terminology.
And it really does not tell me how it works.
But for $6 I would play with it.

So if you used it - is it really a parallel ( RS232 byte ) to serial (RX) and serial (TX) to parallel (RS232) converter via USB / COM harware?
Too bad I cannot read the chip label.
May be usefull for some simple control application.
Thanks
73 Vaclav

No, it's not a wireless module in any form, bluetooth or otherwise. It's a way to add a PC serial comm port by way of the USB bus, nothing more nothing less. Once the device converts the USB data it outputs and inputs serial data to the device it's hardwired to.

The Tx and Rx names are just naming the serial sending and receiving signal wires. There is no parallel data involved. The data is only held in parallel byte form inside the PC software or inside the device that is receiving the serial bit data. The chip type is in the title, CP2102, which is a popular chip.

I think you might be thinking this device does more then it really does?

[WN6U]

Here is the CP2102 data sheet: http://www.silabs.com/Support%20Docu...ocs/cp2102.pdf

The Ebay device only provides access to the TX and RX lines and the RS232 label is "inaccurate".

FTDI makes similar chips.

[W9GB]

Vaclav -

Yes, these are simple USB to serial TTL converters -- BUT only providing the signal lines (Tx, Rx, Gnd) plus DC voltage (+5 or +3.3) from the USB host computer.
The eBay items are from Hong Kong exporters (handling Taiwan and Mainland China products) ---
these items normally have a 2 weeks delivery time,
due to clearance thru US customs and they are sent by AIR on a space available basis.

You can buy the same USB or RS-232 breakout boards (wide selection) from SparkFun Electronics in Boulder, Colorado
http://www.sparkfun.com/categories

IF you want a full RS-232 -- then you need a PC board that brings out the other data lines from USB bridge chip.

BTW, IF you have a local electronics retail store (rare these days) .. they can order and stock SparkFun products !
This is what Radio Shack should have become over past 20 years ... but they can't seem to escape the mobile/smartphone $$

[AD6KA]

Yes, these are simple USB to serial TTL converters -- BUT only providing the signal lines (Tx, Rx, Gnd) plus DC voltage (+5 or +3.3) from the USB host computer.

Add an optoisolator, a couple audio isolation transformers, a few other parts
(all available at Radio Shack) and you can very easily build a USB Digital
interface for PSK31, etc.

[AB9LZ]

Add an optoisolator, a couple audio isolation transformers, a few other parts
(all available at Radio Shack) and you can very easily build a USB Digital
interface for PSK31, etc.

Uh, but kinda not, Not with just tx and rx, most rig keying schemes rely on the data terminal ready line for the keying signal.

73 m/4

[AA7EJ]

Uh, but kinda not, Not with just tx and rx, most rig keying schemes rely on the data terminal ready line for the keying signal.

73 m/4

Actually I am going to use this “device” as a CAT control for my FT 857.
But I have one now so I will hold off for a while.
In this case it is true digital stuff, so I am not sure why I would need audio transformer, but the optocouplers may be vise idea since some folks claim they blew up their CAT (input fuse?) in FT 857.
Cannot confirm that either.

Incidentally, I am finding that true PC serial port – DB9 variety , not full RS232, has a nasty habit of asserting the DTR line when the COM port is just being initialized in software – thus briefly keying the DTR line BEFORE any data are send to the COM port.

So far I have been unable to figure out how to “fix” that using Windows API.

Temporary solution is not to use DTR as key line

[W9GB]

Incidentally, I am finding that true PC serial port – DB9 variety , not full RS232,
has a nasty habit of asserting the DTR line when the COM port is just being initialized in software –
thus briefly keying the DTR line BEFORE any data are send to the COM port.

CORRECT. This issue started with Widnows 2000 / Windows XP.

There were a few issues related the RS-232 RTS and DTR control lines (Hi or Lo state), Microsoft Knowledge base had the configuration changes to defeat this process.
You will have to search the MS databases for specifics, I helped debug that ages ago with W2K ....
and no longer have those MS testing notes.

A related problem for RS-232 (DE-9) serial ports running W2K and WinXP during the "boot and intialization process"
in this same time period (12-13 years ago), was improper detection by MS W2K of devices attached as being the Microsoft Serial Mouse.
That is very important to Windows, since usage of a Mouse is an integral part of the user interface.

This was a problem with the TAPR TAC-2 kit ... adding a configuration line to the file: boot.ini resolved that specific issue.

==
w9gb