YOu can surely convert rs-232 signal levels to USB signal levels. But definition of USB doesn't end there. It includes a lot of other details about comms protocols, handshakes, clocks, addressing, command/ response structure etc etc. There is no equivalent in rs-232 as such. However you could possibly write a driver for the rs-232 (receive end) which responds to USB protocol & hence make it work. But they would be non-standard.
However in the case of USB to rs-232, the converter itself is a USB device & hence has the protocol capability built in. All it then has to do is Tx & Rx at rs-232 levels.
Get it ?
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I am trying to think in a signal conversion level.I used UM232r in which is USB to TTL converter.Which has FT232r which does the main job for the signal conversion from USB to TTL.Basically the signal which we give at the input has to be same as the signal we get at the output ,then we can say the data is proper.So i plug this UM232R to a computer (conect Tx to Rx) and run,it works great..Now if i want to get the data from an Rs-232 device to convert to USB ?? will FT232R be useful ? i mean if i use MAX232 chip to level shift then connect to the FT232R ...
https://www.ftdichip.com/Support/Documents/DataSheets/Modules/DS_UM232R.pdf
OK, but where RS232 comes in? If you need to just implement a serial protocol for exchanging raw data between two PC ports, then you could connect them with each other via two FT232r, or you could use a serial to usb cable.But I looking for a solution or a possible explanation of converting RS-232 - TTL to USB.for example -- Getting USB signal CONVERTING into TTL --> reconverting from TTL to USB ..
As described in post #2, this is a different story. You have to fully implement USB protocol, not just physical layer.i want to connect computer to other USB devices like mouse,printer,scanner....i want to know the problems i have to face and fix.
kdg007 said:for connecting to Mouse i can use UM232r i am guessing.
i might have to keep a storage device,to store the data from the USB and send to the TTL circuit.Storage will convert the speed limit keeping the signal safe..am i right ? cause no matter what kind circuit i design in TTL (op-amp,transistors) ,the speed is the major problem.
....i might have to keep a storage device,to store the data from the USB and send to the TTL circuit.Storage will convert the speed limit keeping the signal safe..am i right ? cause no matter what kind circuit i design in TTL (op-amp,transistors) ,the speed is the major problem.
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I cannot see how this reference contributes to this discussion. This link describes a procedure on how to establish communication between PC's RS-232 port and a specific CNC's RS-232 port, using a specific software.based on post 39 , not the original question. this is all u need 2 do.
**broken link removed**
___Using just a storage-device to somehow match speeds is a Baaa..aad idea. Unless you make many assumptions about the duty cycle/ max tx data etc etc (which a good comms channel should NOT), how will you decide how much to store ? For long bursts of data you will run out of space real quick..., and then what ?
Better is to have a small storage, and a good handshake protocol with the sender/ transmitter to start/ stop transmission.
RS-232 was the defacto serial port for 2 way communication between 2 devices until ethernet for long distance and USB for short distance became default..
Now RS232 is practically obsolete on portable computers ( no serial ports ) and also most new desktop PC's.
That's a pretty good reason why you can't do it. Of couse it could be converted from USB or ethernet or another port, but why would you ever want to?
Of course if you really wanted to setup a 2 way simple communication system, simply get 2 old computers and a cross-over cable and then connect to your really long cable or get a Limited distance Data set (LDDS) as a repeater for the signals.
Since old PC's would use the same Rx and Tx pins, the crossover cable serves the same purpose as a pair of modem's so it was also called a NULL MODEM cable.
They have similar cross-over cables for USB, ethernet and other ports for direct peer to peer connection. Then you need to software to run it.
My favorite auto scripting serial port software was called Q-Modem from MUstang Software in the 70's. It was a great standard tool in the BBS dial-up days.
Other than doing your homework( which I wont) does that answer your question?
Please read post's 7 last reference down to the bottom (pdf file). It's on Human Interface Devices (HID). Speed is not the only issue. You can't escape by just sending raw data. You must implement other things as well.
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