Federal NAC codes

[fpswarrior]

I am trying to compile a list of NAC codes for federal agencies. So far the only 2 that i have been able to kind of figure out is TSA (NAC 001) and ATF (NAC 650). I'd really like to figure out FPS, DHS, ICE, and the VA police, but ANY other NAC codes that any of you fine people have figured out or come across would be appreciated.

 

[Armadillo5]

I was wondering, how are you figuring out or trying to find the correct NAC's?

I know with a normal scanner you can search out the PL and DPL stuff but how are you finding the NAC's?

I have been having a terrible time figuring them out. I did read in another post where the SS has a standard NAC of 001.

It is good to see someone trying to get this started. Thank You.

 

[fpswarrior]

Well i'm trying to use kNACk but i am having a heck of a time, in fact not much luck at all. I've mainly spent hours searching the net for NAC codes and then trying them on my Moto XTS 5K and seeing what NAC code will break the squelch for the various agencies when they TX something. Needles to say its been a frustrating process thus far.

 

[DaveIN]

If you can hold out until this fall, the new GRECOM PSR-500/600 digital trunking scannners will have a the ability to decode NAC during the comm just like ctcss/dcs search. A review of the radio is coming to the Aug. issue of Popular Communications.
http://wiki.radioreference.com/index.php/GRE_Radios
http://www.radioreference.com/forums/forumdisplay.php?f=117

 

[HM1529]

I've seen others report that DEA frequencies are using NAC 156 and FBI frequencies are using NAC 167 (easy to remember since their standard PL's on analog are 156.7 and 167.9).

 

[WayneH]

I've seen others report that DEA frequencies are using NAC 156 and FBI frequencies are using NAC 167 (easy to remember since their standard PL's on analog are 156.7 and 167.9).

This is one of two common methods where an agency doesn't pick a random value and sets it as a standard (e.g., USSS or BATFE). The other method is to take the tone, remove the decimal point, and convert it to hex. BLM and BOI commonly do this. For example, PL 123.0 would be NAC 4CE (or 1230 decimal).

Outside of that, 293 is the most dominant NAC. It's used a LOT. Also, a radio MUST send a NAC. There's no CSQ version; that's for receive only.

 

[trace1]

Well I must get out and learn more...

All P25 Network Access Codes (NAC) will be in conformance with the
attached Continuous Tone Coded Squelch System (CTCSS) to NAC conversion table,
using the CTCSS tones currently authorized for the channel.

Shown below is the conversion table from CTCSS to NAC codes. These codes were
determined by taking the CTCSS frequency and multiplying it by ten, then converting
the integer result to a hexadecimal number.

CTCSS NAC Code
67.0 Hz $29E
69.3 Hz $2B5
71.9 Hz $2CF
74.4 Hz $2E8
77.0 Hz $302
79.7 Hz $31D
82.5 Hz $339
85.4 Hz $356
88.5 Hz $375
91.5 Hz $393
94.8 Hz $3B4
97.4 Hz $3CE
100.0 Hz $3E8
103.5 Hz $40B
107.2 Hz $430
110.9 Hz $455
114.8 Hz $47C
118.8 Hz $4A4
123.0 Hz $4CE
127.3 Hz $4F9
131.8 Hz $526
136.5 Hz $555
141.3 Hz $585
146.2 Hz $5B6
151.4 Hz $5EA
156.7 Hz $61F
162.2 Hz $656
167.9 Hz $68F
173.8 Hz $6CA
179.9 Hz $707
186.2 Hz $746
192.8 Hz $788
203.5 Hz $7F3
206.5 Hz $811
210.7 Hz $83B
218.1 Hz $885
225.7 Hz $8D1
229.1 Hz $8F3
233.6 Hz $920
241.8 Hz $972
250.3 Hz $9C7

... never heard of NAC codes till I read this thread...

 

[gesucks]

Nac

i can tell you that the USMS does not follow that table and uses about 20-30 different NAC codes depending on area in Rx and Tx

 

[10-95]

This is one of two common methods where an agency doesn't pick a random value and sets it as a standard (e.g., USSS or BATFE). The other method is to take the tone, remove the decimal point, and convert it to hex. BLM and BOI commonly do this. For example, PL 123.0 would be NAC 4CE (or 1230 decimal).

Outside of that, 293 is the most dominant NAC. It's used a LOT. Also, a radio MUST send a NAC. There's no CSQ version; that's for receive only.

Actually a NAC of F7E should unsquelch a receiver for all incoming digital traffic...

http://www.p25.com/resources/P25TrainingGuide.pdf

 

[frankh]

I was wondering, how are you figuring out or trying to find the correct NAC's?

I know with a normal scanner you can search out the PL and DPL stuff but how are you finding the NAC's?

I have been having a terrible time figuring them out. I did read in another post where the SS has a standard NAC of 001.

It is good to see someone trying to get this started. Thank You.

This will decode ncs http://www.winradio.com/home/g305-apco25.htm.

 

[com501]

This is one of two common methods where an agency doesn't pick a random value and sets it as a standard (e.g., USSS or BATFE). The other method is to take the tone, remove the decimal point, and convert it to hex. BLM and BOI commonly do this. For example, PL 123.0 would be NAC 4CE (or 1230 decimal).

Outside of that, 293 is the most dominant NAC. It's used a LOT. Also, a radio MUST send a NAC. There's no CSQ version; that's for receive only.

BLM, BOI and USFS commonly do this as they are using Bendix King radios. The normal programming mode for those radios in the digital mode is to display decimal NACS and not hex.

$293 is the default from the factory for most radios. Why, no one knows. I would have thought it would be $001...

The USFWS in this area of Nevada uses NAC 001 and a different TG also, along with their P25.

 

[Armadillo5]

So if I understand this correctly, I have to have the correct NAC programed in my Astro Saber in order to hear let's say the ATF? Or, I have to have the correct NAC programed in to break the squelch?

I have one of their channels plugged in and the only way to hear it is when I open up the squelch on the radio using the button on the side of radio.

Thank You for the help.

 

[n7jei]

Actually a NAC of F7E should unsquelch a receiver for all incoming digital traffic...

http://www.p25.com/resources/P25TrainingGuide.pdf

I also have heard that selecting this NAC for receive is like having a carrier squelch... it will pass all NACs.

 

[com501]

F7E hex or the equivalent decimal NAC will force your radio to operate in "carrier squelch" mode for digital signals.

When I program radios for public safety, I always set the NAC for receive to F7E and the mode to 'mixed' unless the agency has a particular NAC they use.

Of course my XTS has ALL the channels set to that except the specific encrypted ones.

 

[Armadillo5]

So if I use this "generic" NAC it will break the squelch but when the encryption comes along and or is used, I will hear the "white noise" you hear when encryption is used?

I guess this "generic" NAC will not "block" the encryption much like the PL Tone would do?

 

[DaveIN]

If you had the NAC of the radio using encryption, wouldn't it block it if you could ignore the NAC?

 

[WayneH]

If you had the NAC of the radio using encryption, wouldn't it block it if you could ignore the NAC?

No, whether the transmission is clear or secure the NAC is always sent.

Regarding F7E, as I should have been more detailed in my original post, is strictly for repeaters since they require you to enter a NAC and don't offer "CSQ" like they normally do for the analog tone table. And I don't recall F7E ever working for subscriber radios. For radios you have to set it to digital CSQ. I believe there's one other special Fxx NAC for repeaters.

 

[com501]

If you had the NAC of the radio using encryption, wouldn't it block it if you could ignore the NAC?

If you have the correct NAC for a digital transmission, you will hear the encrypted traffic IF YOU HAVE THE CORRECT KEY LOADED. If you do NOT have the correct key or demod type for the encrypted traffic, there are two options.

If your radio IS equipped with encryption, you can select proper code detect FOR HARDWARE ENCRYPTION TYPES ONLY. This feature is supported for Astro radios with DES, AES, and other hardware board add ins.

For ADP (the $10 Moto option) you CANNOT select proper code detect, so any encrypted traffic with the correct NAC will sound like a bad cell phone call from Nextel. The garbled digital squeaks and squeals sound.

Most systems use a specific NAC for an encrypted channel, so if you are monitoring and don't have the correct encryption, you can just choose another NAC or program two channels. One with the correct NAC in case they forget to encrypt (like the FBI occasionally) and one that has a different NAC to 'mute' the encrypted traffic. (The nuisance delete in scan would be used a lot for this!)

Whenever we assign encryption to an agency, that channel is usually (99%) encrypted all the time and the user has no choice. It is hardcoded as 'selected' in the software to eliminate those kinds of user errors.

 

[Armadillo5]

So lets say I program in the correct NAC on channel 1 and then program an incorrect NAC on channel 2....When they go encrypted I can just change to channel 2 and if they stay encrypted I will not hear the "white noise" until they go "clear" and then I will hear them on channel 2?

Sorry to ask these ?'s but so much of this is new to me and I want to be sure I understand this correctly. I am in the process of programing my VHF Astro Saber and there are some P-25 channels worth listening to but I want to block the encryption much like I did with the use of the PL Tone.

I do miss the days when monitoring a scanner was much easier. Just plug in the frequency, PL Tone and away you go. If they went encrypted, that PL Tone would block it and leave me with no "white noise".

 

[WayneH]

So lets say I program in the correct NAC on channel 1 and then program an incorrect NAC on channel 2....When they go encrypted I can just change to channel 2 and if they stay encrypted I will not hear the "white noise" until they go "clear" and then I will hear them on channel 2?

What do you mean by incorrect? Per Com501's example Channel 1 would be one NAC, which would be slaved to encryption only and Channel 2 would be a separate NAC with that channel slaved to unencrypted. You have to have the correct NAC, period. Encryption and NACs operate independently. It's up to the programmer on how they set it up.

All Federal agencies that've I've heard so far (USSS, TSA, BATFE, and VAMC) permit user selectable encryption. I can only think of one occasion where someone used two NACs to separate encryption from clear voice. I've yet to identify the who.

If you're going to use a commercial radio to listen to digital traffic you either have to set it to digital CSQ mode or set the correct NAC. If you're wanting to monitor BATFE set the NAC to $650. This is a nationwide standard output NAC.