Batboard

Hi guys,

Can someone explain how the new 9600 baud system keys work? I've heard that they're more complex in operation to the old style systems?

Cheers,
Matt

I could be mistaken, but I don't think that so-called 9600 baud and system keys have any relation to one another.

One of the problems with digital voice heretofore has been voice quality, which is limited by the data rate. On the other hand, data rate has been limited by frequency when using traditional FSK that only has two states.

So-called 9600 baud modulation involves 4 states of phase shift for each data blip. This effectively permits two bits of data to be encoded per blip, since the four possibilities for consecutive bits are 00, 11, 01 and 10. Whether it is legimate to call this 9600 baud is a question much debated.

Facts sort of distort as they become "I've heard"

Here are some facts. Motorola does have a new "System Key" process, the Advanced System Key which is implemented with the ibutton system. This is much more secure than the original system key.

Once a radio is programmed with an Advanced System key - with CPS - it will NEVER EVER AFTER be possible to program that radio without the Advanced System Key. Period.

Another fact - Astro 25 products - those sold currently for use on 9600 systems - can only be programmed with CPS. There is NO DOS RSS for these radios.

So in a sense - you heard right - systems can be protected by a much more complex system key process. Not all system administrators are using the Advanced Keys yet so some radios can still be programmed with a "homebrew" key, and for the few 9600 baud capable radios that are still being programmed by DOS RSS - there is no ibutton support for the RSS but I would be very surprised if those radios can be programmed by DOS ever again if they get rebanding firmware upgrades.

Read about the ibutton here: http://batboard.batlabs.com/viewtopic.php?t=36119

RKG wrote:I could be mistaken, but I don't think that so-called 9600 baud and system keys have any relation to one another.

One of the problems with digital voice heretofore has been voice quality, which is limited by the data rate. On the other hand, data rate has been limited by frequency when using traditional FSK that only has two states.

So-called 9600 baud modulation involves 4 states of phase shift for each data blip. This effectively permits two bits of data to be encoded per blip, since the four possibilities for consecutive bits are 00, 11, 01 and 10. Whether it is legimate to call this 9600 baud is a question much debated.

Debating that is like debating whether pounds and miles are the same thing

Anyway, exactly what sort of iButtons does Motorola use? Do they use the el cheapo boring 64-bit unique ID ones, or the more secure cryptographic units?

I thought you could still program conventional channels if you have the ASK or not.....Correct me if I'm wrong. I thought that applied only to trunking personalities....

It applies to everything. It does not make sense that you can't change just the conventional data but that is the way it works.