Transceiver Protocol

Wireless & IoT
1

Hi,

I would like to know which protocols are being used nowadays with the transceiver HopeRF RFM12 (not 12b). I intend to use it in a wireless mesh network.

Also, please let me know whether SNAP (Scalable Node Address Protocol) is still a popular choice or whether it has become obsolete now.

Thanks!

2

Probably most folks don’t use a formal protocol. They just exchange data frames of bytes, each with a sequence number and error check (CRC).

I’ve done that, in C, and there are examples.

3

Thanks for the reply.

I was also tempted to come up with my own protocol, but the thing is I would like my system to be compatible with other devices (i.e. there should be interoperability).

In my previous question, I did not mention the specifications of the device I am using: it runs on 433 MHz and uses FSK. So I’d like to know whether a protocol exists for any device having these particular specifications.

4

Left_Jab:
Thanks for the reply.

I was also tempted to come up with my own protocol, but the thing is I would like my system to be compatible with other devices (i.e. there should be interoperability).

In my previous question, I did not mention the specifications of the device I am using: it runs on 433 MHz and uses FSK. So I’d like to know whether a protocol exists for any device having these particular specifications.

In 433MHz FSK data transceivers, I don’t know of any standards for interoperability!

5

I was reading about a standard called Dash7. There’s not much information about it available - for that one has to become a member. Do you have any info on Dash7?

6

Dash7 - vaguely familiar but no, it must not be widely used.

In 433MHz, the transmitter duty cycle is usually very low, to save battery and to avoid generating interference. So protocols from IEEE and the like aren’t there, by my experience.

google took me to

http://www.dash7.org/index.php?option=c … &Itemid=11

where I see that Dash7 is a proprietary spin of ISO 18000-x. That ISO standard is for RFID. It’s curious politically that there are vendors for the ISO 18000-x standards, but seemingly only one per -x. The Dash7 is likely ISO 18000-7. SAVI and others roost on the ISO 18000 protocol and try to assert it’s an open standard but they’d be happy to license you for a small fortune so that if you do your own product with that standard you’ll waste money and risk an intellectual property haggle with the patent trolls.

Anyway, ISO 18000 is RFID oriented (tag ID/status bits) rather than general purpose two-way communication which is the intent of the Hope RF modules’ chip (SI Labs as I recall).