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Thoughts on a wireless terminal?

bobalexander

I find myself and my co-workers in situations where it would be nice to be able to connect wireless to a serial device for configuration.

An example is a piece of networking equipment installed in a cell site cabinet while it is A) freezing cold and snowing B) Extremely hot and sunny or C) Raining

These installations are often out in the middle of a field with no place to sit/rest your laptop. The best solution I have found thus far is to put a length of Cat5 on a reel and spool it out from the van to the cabinet each time.

 

My first question is does anyone else have the same or similar problems?

 

An alternative would be a wireless serial connection. I know there are a few commercial 'ready' devices out there such as the RS232 Bluetooth Wireless Adapters but the price and short range (I highly doubt you are really going to get 300ft with Bluetooth) not to mention lack of features makes this a non-starter for me.

 

XBee is one option

Or even better (price wise): 433Mhz Radio Telemetry Kit

I would like to have a RJ45 jack on the remote end and be able to (if possible) reconfigure Tx/Rx etc dynamically.

9600 baud is generally the speed these devices communicate at.

The far end could be a micro-controller with a battery and the terminal itself could either be a Raspberry Pi etc or a laptop.


So, the primary question is:

Are there any good projects or products out there that solve this problem?

  • 0

    Hi Bob,

     

    You'd need the communication to be secured, so most microcontrollers can be ruled out.

    If it needs to be wireless then the (by far) easiest way is to use a small router with secure VPN capability, 3G/4G access and a serial port - in other words, a 'console server'.

    You could use a raspberry pi, but possibly it wouldn't be authorised by your network team.

    There are quite a few manufacturers for equipment that may meet your network team requirements, personally I wouldn't compromise security or reliability (as you mention,

    the environment can be hot/cold) and would pick a device from a well-known manufacturer rather than the cheapest device in this scenario.

  • 0 in reply to shabaz

    Good point - I didn't mention security, but the over-the-air communication would need to be encrypted.

    I had thought about implementing AES encryption on an AVR such as in this AES on AVR document.

    Alternatively, I have a few PIC18's in my parts bin and could possibly implement it as in this Data Encryption Routines for the PIC18

    It might require it be a second standalone chip just for the encryption but that isn't a big deal.

     

    The reality is that this will only be running when a tech is present and will not be left connected to the host device and that differentiates it from your typical console server.

    I know OpenGear and WTI make great products that can communicate over cellular and Ethernet but that's not what I'm looking for in this application.

     

    Thanks!

  • 0 in reply to bobalexander

    You might want to consider the CC3200 launchpadCC3200 launchpad, also see here for a guide to it. It would be 802.11 based so may meet your range specification. It has SSL capability. And it may work

    at extended temp ranges (I have not checked).

     

    If you can ensure a mechanism to put your own certificate on it, then that may be reasonably secure.

    But, your network team may still be unhappy. They may want specific certifications for the security aspects since this is to connect to cell sites. If that occurs then you'd have to resort to the

    console server method (which is available in portable DC-powered options, doesn't have to be permanently installed).

  • 0 in reply to shabaz

    Great document! I will have to check this system out!

  • 0 in reply to bobalexander

    Great! I hope it will help. A procedure for a secure link for data comms (as best as we can achieve with the technology we have), including how to create and install the certs, would help a lot of people I think. The information is all out there on various sites, but not in a single easy-to-follow workflow today.