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RF Tranceivers: 27997 vs. 27982 — Parallax Forums

RF Tranceivers: 27997 vs. 27982

dfilipdfilip Posts: 5
edited 2012-05-09 15:38 in Accessories
I have serveral of the "old" 433 MHz tranceivers with 2 antenna, model number 27997, previously sold by Parallax.

I see that Parallax no longer sells those, but instead sells a new single antenna RF transceiver, also 433 MHz, model number 27982. The new one uses a pin to switch between transmitting and receiving.

Before I purchase a 27982, I would like to know if it will work with the 27997.

Thanks.
.

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2012-04-30 06:29
    Sorry you haven't gotten a reply so far, probably because no one who has seen your question knows the answer for sure. If you look at the datasheets for the LINX devices used, you'll see that they're simple transmitter / receivers for the 433MHz band. As such, they should be compatible with one another, but I haven't tested them together.
  • dfilipdfilip Posts: 5
    edited 2012-04-30 15:01
    Mike Green wrote: »
    Sorry you haven't gotten a reply so far, probably because no one who has seen your question knows the answer for sure. If you look at the datasheets for the LINX devices used, you'll see that they're simple transmitter / receivers for the 433MHz band. As such, they should be compatible with one another, but I haven't tested them together.

    Thanks for the reply. The way the 'old' 27997 transceivers work is that if the output pin is on ('1') then a continuous 433 MHz signal (sine wave) is sent, and if the output pin is off ('0'), then nothing is sent. So it is a binary on / off signal, nothing more than that.

    Do you know if the 'new' 27982 transceivers work the same way? Or is there any inherent protocol above and beyond simply turning on and off a 433 MHz signal?

    Otherwise, do you know if anyone else still sells the 28997s?

    [Tried Google, but couldn't come up with anything :frown: ]
  • Mike GreenMike Green Posts: 23,101
    edited 2012-04-30 15:31
    All of these 433MHz devices work with simple on/off signalling. All of the programming examples use this on/off signalling to send asynchronous serial data. Most of the examples now include some error detection using a checksum. The documentation and examples are posted on the Parallax webstore page for the product.

    I believe that Parallax changed the design because LINX came up with transceiver chips so Parallax could manufacture just one device instead of three separate devices (27995, 27996, 27997) and most of the use involved some bidirectional signalling, perhaps as simple as an acknowledgement of reception of a message without error.

    I doubt that anyone still sells the 27997 since Parallax doesn't make them anymore.
  • dfilipdfilip Posts: 5
    edited 2012-05-09 15:38
    Mike Green wrote: »
    All of these 433MHz devices work with simple on/off signalling. All of the programming examples use this on/off signalling to send asynchronous serial data. Most of the examples now include some error detection using a checksum. The documentation and examples are posted on the Parallax webstore page for the product.

    I believe that Parallax changed the design because LINX came up with transceiver chips so Parallax could manufacture just one device instead of three separate devices (27995, 27996, 27997) and most of the use involved some bidirectional signalling, perhaps as simple as an acknowledgement of reception of a message without error.

    I doubt that anyone still sells the 27997 since Parallax doesn't make them anymore.

    Thanks for the feedback. It sounds like it should work. I just ordered a couple of 27982's and will test it out myself. I'll update this thread with the results, in the event that anyone else has the same question in the future.
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