Is a Motorola P25 Trunk Control Ch analog?

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mkpowell

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Listening to the Australian GRN Motorola P25 system today I was listening to the 9600 baud control channel stream and it made me ask if that is an analog data stream and NOT a P25 stream?

Anyone? (even other Countries?)

regards

Mat
 

WayneH

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All trunking formats are digital data streams.

An example of an analog signal used to represent data would be DTMF, tone signaling like QuickCall, etc.

When a sine wave is modulated to represent a digital bitstream then it's considered a digital data stream.

Here's an example from Wikipedia how digital data can be expressed in a waveform: http://en.wikipedia.org/wiki/Phase-shift_keying
 
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SCPD

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Listening to the Australian GRN Motorola P25 system today I was listening to the 9600 baud control channel stream and it made me ask if that is an analog data stream and NOT a P25 stream?
The NSW GRN was once a Motorola Omnilink system on 851 Mhz. It was analog but may have support P25 voice. The control channel was 3600 bps. Apparently (according to the DB), they moved to a full P25 digital-only system down around 410 Mhz last year.

What frequencies are you monitoring now?
 

Jay911

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The NSW GRN was once a Motorola Omnilink system on 851 Mhz. It was analog but may have support P25 voice. The control channel was 3600 bps. Apparently (according to the DB), they moved to a full P25 digital-only system down around 410 Mhz last year.

What frequencies are you monitoring now?
GRN moved from Smartzone OmniLink to P25 in 2010/2011. I'm pretty sure the SZ system was on the exact same frequencies... someone local can confirm, but I was keeping close tabs on it for a year or two and there was lots of talk about reusing the frequencies.
 

mkpowell

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Question Solved!

Thanks for everyones replies BTW!

FYI...

The NSW GRN control channel data is not transmitted as "data over P25" because I am using an old analog scanner (with discriminatotr Mod) directly into my PC using Unitrunker and decoding the control channel. The Voice channels are all transmitted as unencrypted P25. (Except for some Groups).

cheers

Mat
 

Jay911

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Hi - all control channels are digital by nature. "Analog" in analog scanner just means analog voice traffic. The discriminator tap doesn't care what format the signal is in - it'll transmit it to the receiving equipment (your PC's sound card) just the same.
 
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