NAC Question

N4DES · Post by **N4DES** » Mon Dec 05, 2005 9:20 am

I read thru some of the older posts and this is what I understand is that:

293 Default NAC code for Motorola

F7E Receiver unsquelch on any incoming NAC
Mobile, Portable, Repeater or Base

F7F Repeater will pass the NAC transparently
Repeater Only

So I decided to try to program F7E into 1 portable and use 293 in the another. The one with F7E didn't unsquelch when I tried to talk to it with the other. Did I miss something in the translation?

Mark

Post by **alex** » Mon Dec 05, 2005 9:45 am

I forget what the option is called -- but in the portables/mobiles (not sure about repeater/base stations) there's a digital CSQ selection which you can use as opposed to choosing a NAC.

Sorry I don't remember where it is in the software - but I would use that to do what your trying to accomplish.

That would allow you to hear anything transmitted with any NAC.

-Alex

N4DES · Post by **N4DES** » Mon Dec 05, 2005 10:03 am

OK...found it. Its in the Conventional Personality/Astro Section at the bottom pull down menu for RX Unmute Rule.

Interesting that F7F didn't do the same thing.

I'll try it again after I have both radios together n see if it does the trick.

Thanks
Mark

MikeOxlong · Post by **MikeOxlong** » Mon Dec 05, 2005 5:03 pm

Just did some experimenting, F7E is indeed the carrier squelch of NAC's. I programmed F7E into one radio setup with Normal Squelch and it unsquelched with the repeater transmitting a NAC of 293.

I then programmed up F7F as a transmit NAC and the repeater refused to key up.

The repeater is a mixed mode Quantar and the portable was an XTS5000.

Have you confirmed that your repeater is indeed keying up when the portable loaded with F7F is transmitting? This would explain why the radio monitoring with a NAC of F7E wasn't unsquelching.

515 · Post by **515** » Mon Dec 05, 2005 6:25 pm

NAC F7E is supposed to be a 'wildcard' NAC, allowing unmute on any received NAC. If you're using conventional talkgroups, make sure you use the 'wildcard' talkgroup of 65535 with it for digital CSQ functionality.

Motorola's original version of Digital CSQ worked fine for receiving, but forced the radio to transmit NAC 293, which isn't always desired. F7E allows the radio to transmit any NAC you program in, but allows the receiver to unmute on reception of any NAC, like transmitting a PL tone but receiving CSQ. Older Motorola P25 gear did not support F7E, and treated it as a regular NAC.

F7F is only supposed to be used in conventional repeaters, as defined by the P25 standard. Programming a repeater with it puts the repeater in "community" mode where it re-transmits any P25 transmission regardless of NAC, and passes the NAC through. Older Motorola P25 gear didn't support this reserved NAC, and treated it as a normal NAC.

According to the P25 standard, the reserved NACs F7E and F7F are not supposed to be transmitted.

N4DES · Post by **N4DES** » Wed Dec 07, 2005 4:31 am

OK...got it and thanks for the info. Currently I'm doing the testing without a repeater in service and just trying to decide on what would be the most logical choice to program the NAC's.

I did find the Digital CSQ in the personality and found it interesting that when I set this flag the TX NAC field is not accessable and gets greyed out like the RX NAC field. So now my question is, with the Digital CSQ set what is the NAC that the radio TX's? Is it the one that was last selected (and is now greyed out) or the default 293?

tvsjr · Post by **tvsjr** » Wed Dec 07, 2005 6:24 am

KS4VT wrote:So now my question is, with the Digital CSQ set what is the NAC that the radio TX's? Is it the one that was last selected (and is now greyed out) or the default 293?

293.

N4DES · Post by **N4DES** » Wed Dec 07, 2005 9:10 am

thanks