Bridge two COM ports in Windows 7?

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kenkeniff

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#177160 24-Jul-2015 09:30

How can I, either using third-party software or natively in Windows 7 x64, bridge two COM ports together?

Device Manager shows:

COM5 is a virtual port connected to a remote hardware device over the internet.

COM9 is a physical port on my PC with a proprietary diagnostics tool attached to it.

I want to connect the two COM ports so that in effect the diagnostics tool is connected to the hardware device over the internet.

kenkeniff

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#1351201 24-Jul-2015 15:20

I found an application that seems to do what I want and allows redirecting virtual and physical ports to each other on Windows: http://www.eltima.com/products/serialsplitter/

I've tested my diagnostics tool however unfortunately it doesn't seem to work.

I believe it may have to do with the fact that the communication from the tool to the machine is DB9 but not RS232.

See schematic below from tool to machine board.

I suspect I may need to convert the pinout to RS232 for the software to work and then back on the other side however maybe someone more savvy with this could advise??

Current setup is:

[TOOL] --- (DB9) -- [PC COM1] - SOFTWARE REDIRECTION - [PC COM2] -- (DB9) --- [MACHINE]

Testing the (DB9) pinout from the machine on the multimeter I get:
1: -3v (2kHz)
2: 3v
3: UNUSED
4: 1.5v (6.8khz)
5: 5v
6: 1.5v
7: 3.5v
8: UNUSED
9: UNUSED

Also using Serial Port Monitor on COM2 I do recieve unintelligible data from the machine.

Another thing is that the diagnostics tool is not externally powered so it may be possible that isn't not getting enough power form the PC?

bazzer

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#1351211 24-Jul-2015 15:42

DB-9 (or DE9) is just a connector isn't it?

So you're sure the remote hardware device is working correctly (i.e. receiving on COM5)?
If so, then can you tell if the program you mentioned is working (i.e. transmitting to COM9)?
If so, then maybe you got the pinout wrong for your tool. I guess you don't have a local hardware device to test with it?

There's a lot to go wrong here probably, so you just have to figure it out bit by bit. Can you capture the COM5 data?

Edit: you updated your post, so some of this might be redundant now.

bazzer

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#1351216 24-Jul-2015 15:50

kenkeniff: I found an application that seems to do what I want and allows redirecting virtual and physical ports to each other on Windows: http://www.eltima.com/products/serialsplitter/

I've tested my diagnostics tool however unfortunately it doesn't seem to work.

I believe it may have to do with the fact that the communication from the tool to the machine is DB9 but not RS232.

See schematic below from tool to machine board.

I suspect I may need to convert the pinout to RS232 for the software to work and then back on the other side however maybe someone more savvy with this could advise??

Current setup is:

[TOOL] --- (DB9) -- [PC COM1] - SOFTWARE REDIRECTION - [PC COM2] -- (DB9) --- [MACHINE]

Testing the (DB9) pinout from the machine on the multimeter I get:
1: -3v (2kHz)
2: 3v
3: UNUSED
4: 1.5v (6.8khz)
5: 5v
6: 1.5v
7: 3.5v
8: UNUSED
9: UNUSED

Also using Serial Port Monitor on COM2 I do recieve unintelligible data from the machine.

Another thing is that the diagnostics tool is not externally powered so it may be possible that isn't not getting enough power form the PC?

3 is TXD, right so maybe you need to wire up a specially mapped cable? I don't know what you mean by "then back on the other side"? Do you mean that these two items usually plug in to each other but now they are in separate locations connected via internet? Then yes, you'll need the inverse cable at the other end. Do you even know what protocol they use to communicate, it might not even be serial?

phantasmNZ

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#1351224 24-Jul-2015 16:17

If possible remove the unknowns.

If you can access the kit at the remote end, or set up another of the "virtual COM" ports to a PC then this will help. Connect the local serial port to another PC so you have

PC == Internet == Virtual Com Port == COM bridge Software == Local COM Port == Another PC

if this all works (ie a serial console open on both PCs at either end) then it should work with your proprietary device (assuming it IS RS232 Serial and you have the BAUD rates etc correct).

Note about your "unintelligable" data - do you have the correct BAUD (port speed) settings?-

Good Luck
P

grant_k

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#1351267 24-Jul-2015 17:47

The presence of SCLK & CLK signals indicates that you are dealing with a 'Synchronous' serial port here, not RS232 which is usually asynchronous and has voltages +/- 12V rather than 3.3V or 5V as you have measured. RS232 ports also don't have a VCC signal (presumably 5V). I had a look at the pinouts for SPI bus as that is what your pinouts most closely resemble, but it's not quite right for that either, so I would say you have one very weird serial port which is certainly not going to communicate with a standard RS232 port. You need to get hold of more information and try to match it up with some sort of serial adaptor in order to convert to RS232.

kenkeniff

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#1351476 25-Jul-2015 10:17

To clarify I do have a local machine and tool that I can test.

I plug the tool directly into the machine and it works fine (display on tool shows correct info).

The next step was to try get it working through COM port redirection (locally through one RS232 port on my PC and out another, not over the internet).

That is what I was referring to here:

[TOOL] --- (DB9) -- [PC COM1] - SOFTWARE REDIRECTION - [PC COM2] -- (DB9) --- [MACHINE]

grant_k: The presence of SCLK & CLK signals indicates that you are dealing with a 'Synchronous' serial port here, not RS232 which is usually asynchronous and has voltages +/- 12V rather than 3.3V or 5V as you have measured. RS232 ports also don't have a VCC signal (presumably 5V). I had a look at the pinouts for SPI bus as that is what your pinouts most closely resemble, but it's not quite right for that either, so I would say you have one very weird serial port which is certainly not going to communicate with a standard RS232 port. You need to get hold of more information and try to match it up with some sort of serial adaptor in order to convert to RS232.

I suspect you're right here which is why I think I need some way of converting the machine output to RS232 in order to connect to PC COM1 and redirect to COM2, and then convert back from RS232 to it's current format for connect to the tool.

My question is is this likely to be able to be done simply by rearranging the pinout or will it require translation of the signals too?

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grant_k

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#1351480 25-Jul-2015 10:31

kenkeniff: To clarify I do have a local machine and tool that I can test.

I plug the tool directly into the machine and it works fine (display on tool shows correct info).

The next step was to try get it working through COM port redirection (locally through one RS232 port on my PC and out another, not over the internet).

That is what I was referring to here:

[TOOL] --- (DB9) -- [PC COM1] - SOFTWARE REDIRECTION - [PC COM2] -- (DB9) --- [MACHINE]

I'm certain that the signals between the machine and tool are not RS232, so my suggestion would be to go back to the manufacturer and try to get an adaptor which facilitates this conversion.

kenkeniff:
grant_k: The presence of SCLK & CLK signals indicates that you are dealing with a 'Synchronous' serial port here, not RS232 which is usually asynchronous and has voltages +/- 12V rather than 3.3V or 5V as you have measured. RS232 ports also don't have a VCC signal (presumably 5V). I had a look at the pinouts for SPI bus as that is what your pinouts most closely resemble, but it's not quite right for that either, so I would say you have one very weird serial port which is certainly not going to communicate with a standard RS232 port. You need to get hold of more information and try to match it up with some sort of serial adaptor in order to convert to RS232.

I suspect you're right here which is why I think I need some way of converting the machine output to RS232 in order to connect to PC COM1 and redirect to COM2, and then convert back from RS232 to it's current format for connect to the tool.

My question is is this likely to be able to be done simply by rearranging the pinout or will it require translation of the signals too?

The only vague connection with RS232 is the DB9 connector; everything else is nothing like it. You will need something with a synchronous serial port of some kind -- maybe an Arduino or Raspberry Pi with appropriate adaptor. Then write some software and connect a standard RS232 port via USB adaptor and you will be in business.

It's an awful lot of trouble to DIY something for a one-off like this, hence my suggestion of going back to the manufacturer, as they may have already done this. Some further info. on the serial port protocol and which standard they've used (if any) would also be helpful.

kenkeniff

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#1351501 25-Jul-2015 11:24

grant_k:
The only vague connection with RS232 is the DB9 connector; everything else is nothing like it. You will need something with a synchronous serial port of some kind -- maybe an Arduino or Raspberry Pi with appropriate adaptor. Then write some software and connect a standard RS232 port via USB adaptor and you will be in business.

It's an awful lot of trouble to DIY something for a one-off like this, hence my suggestion of going back to the manufacturer, as they may have already done this. Some further info. on the serial port protocol and which standard they've used (if any) would also be helpful.

It's rather difficult getting this sort of info from the manufacturer as there are a few barriers including language, I will continue down that path however it's not guaranteed.

My use case is that there are a number (>50) of these machines deployed in remote areas. I have remote access to a PC's controlling them but no remote access to the diagnostics port on the machine.

I was attempting to use the control PCs to gain remote access to the diagnostics port when necessary.

I don't need 24/7 access to the ports, just the ability to dial in when needed. Client-side interaction to establish the connection would also be OK.

Perhaps there is another way I can establish a raw remote connection to this port independent of the protocol used? (Through PC, internet, dialup etc?)

richms

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#1351524 25-Jul-2015 11:32

You would need to make something that deals with their propriatary protocol, understands it well enough to re-package it into a standard serial data stream and then send that over the network to the other end and have something do the opposite.

Then you would need to make sure that the gear was happy to have the added latency to its protocol without it totally screwing up and causing errors.

Richard rich.ms

kenkeniff

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#1351549 25-Jul-2015 12:24

richms: You would need to make something that deals with their propriatary protocol, understands it well enough to re-package it into a standard serial data stream and then send that over the network to the other end and have something do the opposite.

Then you would need to make sure that the gear was happy to have the added latency to its protocol without it totally screwing up and causing errors.

I would be interested if anyone here could deliver such a solution.

kenkeniff

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#1353581 28-Jul-2015 17:16

I found another wiring diagram for the connection which confirms SSI; looking up on it I'm wondering if a couple of RS422 to RS232 adapters would do the trick?