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Can you use serial communications on ethernet?

Discussion in 'General Electronics Discussion' started by chopnhack, Jan 27, 2015.

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  1. chopnhack

    chopnhack

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  2. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    That instructable doesn't make the serial port accessible on an Ethernet LAN; it just adapts one type of connector to the other, so you can send serial data over a piece of Ethernet cable!

    To do what you want, you would need a microcontroller-based board that implements the Ethernet protocols and provides an addressable serial device that can be interrogated from another Ethernet device using the Ethernet protocols.

    I know nothing about this, so that's all I can say. I think there are others here who know the ins and outs of Ethernet and can tell you more.
     
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  3. Harald Kapp

    Harald Kapp Moderator Moderator

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    The instructable may not be what you are looking for. It is not a seerial-to-ethernet converter. All it shows is how to connnect an RJ45 connector to a DB9 connector. This is not Ethernet!

    I think you are looking for a converter which allows you to communicate with the converter via Ethernet and the converter connects to the end device via a serial port. Google "serial over Ethernet" for suitable products.
     
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  4. chopnhack

    chopnhack

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    Apparently the device was one revision away from an onboard ethernet! :( as such I was informed that the chipset is not even on the board and thus not compatible!

    Thank you both for the information.
     
  5. BobK

    BobK

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    If you have a serial port on your PC, all you need is some software to take serial port data and forward it over the internet. If you do not have a port, you can get a serial to USB converter that will give you a serial port.

    Bob
     
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  6. Gryd3

    Gryd3

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    We've had another user on here talk about an ethernet device to do this.
    It's a Serial Ethernet Bridge : http://www.dcbnet.com/datasheet/etherbridge.html

    You can DIY with an computer, or a microcontroller.
    (Edit... of course they charge a lot of money for them... you can't exactly get them from RadioShack so they attempt to grip your manly parts by charging well over a couple hundred $ for maybe $30 in parts)
     
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  7. chopnhack

    chopnhack

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    Indeed! My first post had a link to what I was thinking of using, but the main board doesn't have the brain on board to manage the operations I was looking for. Such is life.
    Thanks!
     
  8. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    Would a Raspberry Pi do this? Or a BeagleBone?
     
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  9. chopnhack

    chopnhack

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    It's possible. The third party device has RS 232 and 485? communication potentials.
     
  10. Gryd3

    Gryd3

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    Good call Kris.
    I don't see why they can't.
    You could send the stream as plain text, or encrypt it. It could be sent via TCP for a more accurate delivery at the expense of a bit of a delay in transmitting and additional overhead, or you could send it via UDP which would be a lower latency link (but would be missing error correction)

    This would depend on what chopnhack plans to 'bridge' over Ethernet.
    If you can afford to buffer, transmit, and playback I would recommend TCP.
    Otherwise UDP... but remember that UDP may drop packets so a portion of the original serial stream may be lost... if the end-points can compensate it should be fine.

    I have a pair of Raspberry Pi I can try here in a LAN environment.
     
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  11. chopnhack

    chopnhack

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    This would be for accessing and alarm panel via smartphone. The vendor has third party application on google store, but since the board does not have a ethernet jack, I was told the board was one revision too old. The serial port allows for connectivity to the web via a different app. It may be something I can backdoor by running a home server to host the software and then connect the server to the serial port. Slow, but sure. The remote access would more than likely be very clunky - smartphone would need to remote into the server and access the hosted program.

    Why is technology so difficult? :mad:
     
  12. Gryd3

    Gryd3

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    It's not difficult, it's interesting!
    Because of the function... instead of bridging serial over ethernet, why not just build a web-based front-end on a RaspberryPi and use it to directly communicate with the serial connection on the Alarm? The Pi (or other device) would completely deal with timing and 2-way communications without worrying about latency or other potential network issues.
     
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  13. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    Are you suggesting a text window like a terminal? So you can type on it and that's sent to the alarm unit through its serial port, and anything it sends back is displayed in a text window?

    John, how is the alarm unit's serial port normally used? Do you connect it to a terminal and communicate with it using text? Or does the manufacturer have a special program to interrogate it, using a special protocol? Do you have any way of interrogating it locally at the moment?
     
  14. chopnhack

    chopnhack

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    And exceedingly frustrating!! I think Microsoft had a hand in the design :rolleyes:

    Very elegant solution.... me likey very much :D - I will save this for future reference when my to do list is smaller. I am in the investigating phase right now! My first option of scrapping and starting all over was not very appealing. You wouldn't believe me if I told you the price of these systems now :eek:

    Kris, the system has two consoles that have LCD readouts, but no, the system is limited to predefined textual output based on triggers - i.e. a zone triggers an event whether that be a door open or a motion sensor, etc. It was also a home automation system that was very cool a decade ago, was using x10 to be able to turn lights on, etc. Yesteryear's cats meow is todays stinky garbage :D:D I would like to extend its longevity by being able to access it via smartphone, I think it will be a cool project. The manufacturer has a program that has to be purchased to communicate with the serial port. I am not sure of the protocol. I have a manual somewhere, I will have to dig into it further to see if its proprietary or open.

    Thanks to both of you!! I will certainly pursue this, just after I finish get a better footing on programming, write code for the dust collector project, install said project, paint the house.... you know ;):p
     
  15. Gryd3

    Gryd3

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    I was thinking of a simple webpage with pre-defined buttons and perhaps a status read-out.
    Because this would be coupled directly to the alarm, I would highly discourage a console of any kind that could allow unknown or malformed information to be sent to the alarm.
    The web-based front end would communicate to the user. (ie, on any phone, or tablet.), the back-end could be written in a number of languages and would be the intermediary in which the alarm would communicate to.
     
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  16. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    OK, so it transmits information when events occur. You could try capturing that data through the serial port in a PC or other device. If you have an oscilloscope you can look at the data stream and figure out the bit rate, otherwise you'll have to try them all one at a time. You may find that the information it transmits is plain text and has a standard format that can be parsed (e.g. by a script running on a web server) and converted into events or information for display on a web page.
    Good luck with that!
    Ah, you're taking it easy these days are you? :)
     
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  17. chopnhack

    chopnhack

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    Trying to keep all the pieces together :eek:
     
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