USB-Serial Cable + Terminal

[Spencer E.]

Is anyone having trouble with using a USB-Serial cable to recieve information in the Terminal window? I don't know if it's the software or the cable but whenever I load a program onto the FRC RC, I get nothing back . If anyone has any idea what the problem is or what to do, it would be greatly appreciate for your help.

[AMIRAM]

Originally Posted by Spencer E.

Is anyone having trouble with using a USB-Serial cable to recieve information in the Terminal window? I don't know if it's the software or the cable but whenever I load a program onto the FRC RC, I get nothing back . If anyone has any idea what the problem is or what to do, it would be greatly appreciate for your help.

Hi

i tried to connect it ones to another app and it didnt work becuse the usb is 5v and the computer serial is -+12v in our RC we have dc-dc converter....

also u should check the usb-serial driver is win-xp compatible


Amiram

[Bruce Mather]

USB to RS-232 Cables...

Many laptops today do not include RS-232 ports or even parallel ports...They have all moved to USB ports. That means, the USB-(insert obsolete port here) market has grown for backward compatibility. A USB port is much more complicated than RS-232 because it includes the plug-n-play protocol on top of the simple serial interface. This means, the device identifies what it is when you plug in a USB cable from a gizmo (digital camera, flash drive, etc.). The old RS-232 port has no such protocol built into any OS (that I know of).

It is true that USB provides 5 volts at some nominal current sourcing level (?) and that RS-232 uses +/- 12 volts as its signalling level. However, USB-to-RS232 conversion cables (perhaps with a module) include built in level converters (charge pumpts, DC/DC converters) which understand the RS-232 voltage levels. And...when you plug this cable into a USB port, it will identify itself (ala firmare actually in the cable IC) that it is a "COM port" device. You may need drivers (from included CD) to be installed.

The problem may be more recognition of the COM port name/number by the software. Many times, USB ports are numbered around 10, 11, etc. rather than starting at 1 (COM1. The software must know which "virtual" com port it is opening and talking to. So see if the USB driver supports a given range of com port numbers and make sure it matches the application port number.

[JBotAlan]

I am using a USB-to-serial cable and I have a tip for you:

If the thing came with a drivers CD, make sure you are using that driver. Don't upgrade, or use an alternative. The cable I have registered as a "Prolific USB-to-comm" or something like that, and Windows automatically used the Microsoft-written driver for it. I was having communication issues, where there was no response from whatever I was talking to (the CMUcam, the RC). I upgraded the drivers with the ones on the CD, and it has worked flawlessly since then.

Also, you could try to go to the manufacturer's website for drivers, but I tried that on another machine and the best drivers produced blue-screen "stop" errors...not fun.

Good luck with this, because I know how much of a pain in the *** these things can be.

JBotAlan