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#1
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USB to RS232 to USB adapter needed
Hello,
I am trying to send RS232 data from two notebooks that do not have serial ports. I know there are USB to serial (RS232) adapters available. These allow communications to occur through a virtual serial port. Now, what I need is a USB to USB RS232 serial cable, that allows serial transmissions to occur, but via USB connections. Can someone please point me in the right direction? Thanks Mike |
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#2
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USB to RS232 to USB adapter needed
Gogle it:
http://www.google.com.pe/search?rlz=...+RS232+adaptor eljainc wrote: Hello, I am trying to send RS232 data from two notebooks that do not have serial ports. I know there are USB to serial (RS232) adapters available. These allow communications to occur through a virtual serial port. Now, what I need is a USB to USB RS232 serial cable, that allows serial transmissions to occur, but via USB connections. Can someone please point me in the right direction? Thanks Mike |
#3
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USB to RS232 to USB adapter needed
eljainc wrote:
Hello, I am trying to send RS232 data from two notebooks that do not have serial ports. I know there are USB to serial (RS232) adapters available. These allow communications to occur through a virtual serial port. Now, what I need is a USB to USB RS232 serial cable, that allows serial transmissions to occur, but via USB connections. Can someone please point me in the right direction? Thanks Mike There is an example here. I picked this one, to demonstrate the physical appearance of such a cable. Note that there is a "blob" in the center of the cable, and identical USB connectors on each end. The blob being dead center on the cable, hints at its unique characteristics (some buffer cables have a blob as well, but the blob is very close to one end of the cable). http://www.newegg.com/Product/Produc...82E16812200198 Software is the important part of such a linking device. There is a chip, inside the blob. Its job is to logically isolate the two sides - USB is not designed for direct peer to peer connections. What one computer sees, is a USB chip with a FIFO peripheral buffer in it. The computer writes to the FIFO buffer. The "other side" of the chip, then forwards what shows up in the FIFO, to the other computer. The other computer is regularly polling the device, to see if anything has shown up. So the chip functions as a "bidirectional mailbox". Computer A ------ FIFO ----------- Computer B ------ FIFO ----------- Windows does not understand what this device does. It takes a software overlay or driver, to make the device do something useful. One instance of this, may be referred to, as a member of the "Laplink" family. I've seen two options offered by such software. One, offers a complete TCP/IP stack. That fools Windows into thinking the USB blob is a network interface. If you enabled File Sharing on one of the computers, and used the TCP/IP version of software, then copying files would be the same as normal File Sharing. The other version of software, implements a "File Transfer" wizard interface. There is no TCP/IP stack in that case, and no network addresses are used. You get a dialog box similar to some of the old FTP transfer programs. One side of the window shows the local disk selected, the other side shows the remote device and its disk. You can copy files via that window, in the same way you would have with the old FTP software. So, in purchasing these things, you want 1) Software CD. Should include documentation. Preferably, there should be a web site that details what the software will do for you. Just purchasing the "cable with blob" by itself, doesn't guarantee it will do anything. The hardware is pretty useless, without good software. A software package that includes both the TCP/IP stack, and the Transfer Wizard style software, offers the most flexibility. (The Newegg page mentions some capability built into Windows called "Easy Transfer", but I have no idea what they're referring to there. A good software package, should make it so you can connect a Win98 machine to your other computer, and transfer files.) 2) The "blobs" come in two flavors. The original one was USB 1.1 speed only. It would transfer your files, but at only 1 megabyte per second. Later, a USB2 version of the chip was made, that really worked at USB2 rates. One company decided to make a copy of this chip, but I think they were slapped with patent litigation and had to discontinue their product. I don't know who, if anyone, still makes the chips. This knowledge is only important if you're buying from Ebay, and some scammer has located some of the older, slower products. Another example here. http://www.usbfiletransfer.com/ This is an example of a chip used inside the blob. This one is USB 1.1 rate only. I'm including this, to give a better diagram of the FIFOs used to isolate the two computers from one another. Notice how the chip maker promises drivers for a version of Win95 (and that is a typical reason why people want these cables - for transferring files between computers that share very little in common). http://www.prolific.com.tw/eng/Products.asp?ID=19 HTH, Paul |
#4
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USB to RS232 to USB adapter needed
"eljainc" wrote in message
... Hello, I am trying to send RS232 data from two notebooks that do not have serial ports. I know there are USB to serial (RS232) adapters available. These allow communications to occur through a virtual serial port. Now, what I need is a USB to USB RS232 serial cable, that allows serial transmissions to occur, but via USB connections. Can someone please point me in the right direction? Thanks Mike I have to use this kind of thing regularly, and they *are* the USB to serial adapters you mention. You just need to add a standard serial cable as the missing component. These are readily available starting around $15 or so. They come with a driver disk that you will need to use. You can also get ExpressCard versions (ExpressCard is the replacement for PCMCIA cards) but these are much more expensive. Note that these units are *not* all the same quality, and on some systems (such as Dell laptops) only specific brands of adapter (IIRC it's CoolGear), meaning specific chipsets, will work reliably. Other units can lead to temporary system freezing. To use serial cables, you just need a pair of the USB-serial adapters and the serial cables, plus whatever crosswire adapters are needed. In the case of real-time court reporting equipment, most of which still requires serial ports, specific crosswired adapters are required depending on the brand of the distribution kit. So, there are at least three readily available components required in the setup. Crosswire adapters may or may not be required or easy to get; in some cases you might need a standard null-modem adapter. You should be able to determine this from the documentation for the software that requires the serial connection. Alternately, you can ditch all these cables and adapters completely by using Serial-to-TCP redirector software. This is a small redirector utility that's run on each system, and each license costs in the $100 range, and you need at least two - there are free demo versions so you can try it out. The demos are full-function but time-limited, and I've used this on both XP and Vista successfully and reliably. Once it's installed and configured, you use the existing network cabling *or wireless connection* and do not have to bother with serial cabling. This can work very well, and is what we have gone to. An example is TCP-Com, by TalTech. Google "Serial to TCP" for more information. HTH -pk |
#5
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USB to RS232 to USB adapter needed
"Paul" wrote in message
... eljainc wrote: Hello, I am trying to send RS232 data from two notebooks that do not have serial ports. I know there are USB to serial (RS232) adapters available. These allow communications to occur through a virtual serial port. Now, what I need is a USB to USB RS232 serial cable, that allows serial transmissions to occur, but via USB connections. Can someone please point me in the right direction? Thanks Mike There is an example here. I picked this one, to demonstrate the physical appearance of such a cable. Note that there is a "blob" in the center of the cable, and identical USB connectors on each end. The blob being dead center on the cable, hints at its unique characteristics (some buffer cables have a blob as well, but the blob is very close to one end of the cable). http://www.newegg.com/Product/Produc...82E16812200198 Software is the important part of such a linking device. There is a chip, inside the blob. Its job is to logically isolate the two sides - USB is not designed for direct peer to peer connections. What one computer sees, is a USB chip with a FIFO peripheral buffer in it. The computer writes to the FIFO buffer. The "other side" of the chip, then forwards what shows up in the FIFO, to the other computer. The other computer is regularly polling the device, to see if anything has shown up. So the chip functions as a "bidirectional mailbox". Computer A ------ FIFO ----------- Computer B ------ FIFO ----------- Windows does not understand what this device does. It takes a software overlay or driver, to make the device do something useful. One instance of this, may be referred to, as a member of the "Laplink" family. I've seen two options offered by such software. One, offers a complete TCP/IP stack. That fools Windows into thinking the USB blob is a network interface. If you enabled File Sharing on one of the computers, and used the TCP/IP version of software, then copying files would be the same as normal File Sharing. The other version of software, implements a "File Transfer" wizard interface. There is no TCP/IP stack in that case, and no network addresses are used. You get a dialog box similar to some of the old FTP transfer programs. One side of the window shows the local disk selected, the other side shows the remote device and its disk. You can copy files via that window, in the same way you would have with the old FTP software. So, in purchasing these things, you want 1) Software CD. Should include documentation. Preferably, there should be a web site that details what the software will do for you. Just purchasing the "cable with blob" by itself, doesn't guarantee it will do anything. The hardware is pretty useless, without good software. A software package that includes both the TCP/IP stack, and the Transfer Wizard style software, offers the most flexibility. (The Newegg page mentions some capability built into Windows called "Easy Transfer", but I have no idea what they're referring to there. A good software package, should make it so you can connect a Win98 machine to your other computer, and transfer files.) 2) The "blobs" come in two flavors. The original one was USB 1.1 speed only. It would transfer your files, but at only 1 megabyte per second. Later, a USB2 version of the chip was made, that really worked at USB2 rates. One company decided to make a copy of this chip, but I think they were slapped with patent litigation and had to discontinue their product. I don't know who, if anyone, still makes the chips. This knowledge is only important if you're buying from Ebay, and some scammer has located some of the older, slower products. Another example here. http://www.usbfiletransfer.com/ This is an example of a chip used inside the blob. This one is USB 1.1 rate only. I'm including this, to give a better diagram of the FIFOs used to isolate the two computers from one another. Notice how the chip maker promises drivers for a version of Win95 (and that is a typical reason why people want these cables - for transferring files between computers that share very little in common). http://www.prolific.com.tw/eng/Products.asp?ID=19 HTH, Paul As I understand it, this cable and its software, while useful, doesn't create an actual or virtual serial port. Depending on the unknown application the OP has to use, that can be extremely important, and a deal-killer. For example, most real-time court reporting systems still output *only* to a serial port (or a specific server you might pay tens of thousands of dollars for). They don't know anything at all about what to do with an IP address or a USB port, or a file transfer window. We have regularly used the USB to serial adapters the OP already knows about - you just need the serial cabling and whatever crosswire adapters are specific to the distribution kit, or even better, Serial to TCP redirector software that allows you to use existing network structures, wired or wireless. These create a virtual serial port that the software can't distinguish from hardware. Works great, and removes the need for extra cabling entirely. Hard to say, though, without knowing what the OP is actually trying to accomplish and the software in question. HTH -pk |
#6
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USB to RS232 to USB adapter needed
Very informative replies. Thanks
We actually have used the USB-USB network bridge (the purple USB 1.1 version from Laplink). While they had their usefulness for a previous purpose, I am not sure if they will work for this case, unless we do use a serial to IP redirector in conjunction with this device. If that is the case the laplink USB-USB network bridge wouldn't be needed. Would it be possible to piggyback two of these USB to RS232 devices together so that each end would have the USB connction, then connect the two DB9 connectors together. Would this present a major conflict or could the device data be transferred both directions? Just a thought. |
#7
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USB to RS232 to USB adapter needed
eljainc wrote:
Very informative replies. Thanks We actually have used the USB-USB network bridge (the purple USB 1.1 version from Laplink). While they had their usefulness for a previous purpose, I am not sure if they will work for this case, unless we do use a serial to IP redirector in conjunction with this device. If that is the case the laplink USB-USB network bridge wouldn't be needed. Would it be possible to piggyback two of these USB to RS232 devices together so that each end would have the USB connction, then connect the two DB9 connectors together. Would this present a major conflict or could the device data be transferred both directions? Just a thought. Sure. Either idea will work. The "blob" idea offers high thruput, but requires the right software to get it to work. (I don't know if USB.org has defined an official class definition for the thing or not.) The USB-to-serial idea has the advantage that it looks like a serial port, so more software may work with it. Just make sure you use the right DB-9 to DB-9 cable to connect them together, and that the devices have the feature set you're looking for (hardware flow control, high baud rates, or whatever). You can get some pretty fancy ones. http://www.ftdichip.com/Products/FT232BM.htm Paul |
#8
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USB to RS232 to USB adapter needed
"eljainc" wrote in message
... Very informative replies. Thanks We actually have used the USB-USB network bridge (the purple USB 1.1 version from Laplink). While they had their usefulness for a previous purpose, I am not sure if they will work for this case, unless we do use a serial to IP redirector in conjunction with this device. If that is the case the laplink USB-USB network bridge wouldn't be needed. Would it be possible to piggyback two of these USB to RS232 devices together so that each end would have the USB connction, then connect the two DB9 connectors together. Would this present a major conflict or could the device data be transferred both directions? Just a thought. That's a case where you might, or might not, need a null-modem adapter, which simply flips a couple of wires to allow direct connection like this. The documentation for the app should tell you this. IIRC, the old LapLink serial cables were essentially null-modem cables. Despite the cost, I can recommend the serial-to-TCP redirector software. It can bypass a lot of issues and considerations common to serial devices, and add significant features, such as longer cable runs, more connecting systems and net broadcast; similarly, there can be security issues. Check out the free demo versions; these usually work for two weeks or so, plenty of time to see if it works for you (and possibly to complete the task). They install in minutes. A big factor in what will work best is whether you absolutely have to use a serial port for the app in question. HTH -pk |
#9
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USB to RS232 to USB adapter needed
"eljainc" wrote in message ... Hello, I am trying to send RS232 data from two notebooks that do not have serial ports. I know there are USB to serial (RS232) adapters available. These allow communications to occur through a virtual serial port. Now, what I need is a USB to USB RS232 serial cable, that allows serial transmissions to occur, but via USB connections. Can someone please point me in the right direction? There are many of these devices available and googling 'USB to RS232' only gets you a mere 5,830,000 hits. However, anecdotal evidence suggest that although these devices work well most of the time, the odd bit of software is ocassionally encountered on ocassion that will not operate well or at all with these converters. |
#10
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USB to RS232 to USB adapter needed
All very interesting. I have been using an ATEN UC232a converter for dumping
data into my XP laptop. This converter has performed fine until the past few weeks. I now cannot download via the converter. I keep getting 'com port may be in use' error. This is no matter what port I select. I have also confirmed what port the unit is running on via Device manager with still no success. I am thinking a recent windows update has effected. I do not know the exact date that this occurred as I used the link successfully 4 weeks or so ago. Therefore I do not wish to roll my system back that far. I will consider using a new converter if I know it will work today. I have sent several emails to ATEN without a reply to date. Any suggestions are appreciated "M.I.5¾" wrote: "eljainc" wrote in message ... Hello, I am trying to send RS232 data from two notebooks that do not have serial ports. I know there are USB to serial (RS232) adapters available. These allow communications to occur through a virtual serial port. Now, what I need is a USB to USB RS232 serial cable, that allows serial transmissions to occur, but via USB connections. Can someone please point me in the right direction? There are many of these devices available and googling 'USB to RS232' only gets you a mere 5,830,000 hits. However, anecdotal evidence suggest that although these devices work well most of the time, the odd bit of software is ocassionally encountered on ocassion that will not operate well or at all with these converters. |
#11
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USB to RS232 to USB adapter needed
All very interesting. I have been using an ATEN UC232a converter for dumping
data into my XP laptop. This converter has performed fine until the past few weeks. I now cannot download via the converter. I keep getting 'com port may be in use' error. This is no matter what port I select. I have also confirmed what port the unit is running on via Device manager with still no success. I am thinking a recent windows update has effected. I do not know the exact date that this occurred as I used the link successfully 4 weeks or so ago. Therefore I do not wish to roll my system back that far. I will consider using a new converter if I know it will work today. I have sent several emails to ATEN without a reply to date. Any suggestions are appreciated "M.I.5¾" wrote: "eljainc" wrote in message ... Hello, I am trying to send RS232 data from two notebooks that do not have serial ports. I know there are USB to serial (RS232) adapters available. These allow communications to occur through a virtual serial port. Now, what I need is a USB to USB RS232 serial cable, that allows serial transmissions to occur, but via USB connections. Can someone please point me in the right direction? There are many of these devices available and googling 'USB to RS232' only gets you a mere 5,830,000 hits. However, anecdotal evidence suggest that although these devices work well most of the time, the odd bit of software is ocassionally encountered on ocassion that will not operate well or at all with these converters. |
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