Determining Tone A and Tone B

[Maxagonzales]

Hi everyone,

I’m reaching out to see if anyone here might be able to assist me with identifying the two-tone alert tones (Tone A and Tone B) used by the Rural/Metro Fire Department in the Tucson, Arizona area. I’ve attached an audio clip that contains what I believe is the actual alerting tones used during dispatch, and I’m hoping someone with the right tools or experience can help me determine the exact frequencies.

Unfortunately, I don’t have the decoding equipment necessary to analyze the tones myself. I’m relatively new to working with pagers and two-tone alerting, and I don’t currently have access to a decoder or software that can accurately read and measure these tones from the audio. What I do have is a Unication G5 pager, and my goal is to program it so that I can receive and monitor Rural/Metro dispatches properly.

If anyone is familiar with the tone pairs Rural/Metro uses, or if you’re able to analyze the audio and determine the tone frequencies, I would be extremely grateful for your help. Even just pointing me in the right direction would be appreciated.

Additionally, I’d be interested to know if there’s a known VHF frequency or channel that Rural/Metro Fire typically uses for dispatch or fireground operations. I’ve been researching online and scanning local frequencies, but I haven’t been able to confidently identify which ones are active for this department.

If it helps, I’m located in the Tucson area, so this is specific to Southern Arizona operations – not Phoenix or Maricopa County.

Thank you in advance to anyone who can offer advice, guidance, or technical assistance. I know this community has a wealth of knowledge, and I appreciate the time you take to help folks like me get started and get set up properly.

Looking forward to hearing from you.

– Max

 

[cmjonesinc]

I believe you forgot the attachment

 

[Maxagonzales]

Could I email it to you? Here’s mine if you wana send yours. Max.gonzales.845@gmail.com it wouldn’t let me send it on here because wrong format. This is an audio format

 

[RaleighGuy]

Unfortunately, I don’t have the decoding equipment necessary to analyze the tones myself. I’m relatively new to working with pagers and two-tone alerting, and I don’t currently have access to a decoder or software that can accurately read and measure these tones from the audio. What I do have is a Unication G5 pager, and my goal is to program it so that I can receive and monitor Rural/Metro dispatches properly.

If you have a G5 with new FW and PPS you have the tools, look in the menus for TONE DETECT and it will decode the tones for you.

 

[Maxagonzales]

can i do this on a trunked system or does this have to be VHF for tone detection

 

[cmjonesinc]

Could I email it to you? Here’s mine if you wana send yours. Max.gonzales.845@gmail.com it wouldn’t let me send it on here because wrong format. This is an audio format

Sent you an email

 

[cmjonesinc]

can i do this on a trunked system or does this have to be VHF for tone detection

My area still tones out over analog with just voice over a digital trunked system. I don't think you'll be able to detect a tone that's been digitized but I'm not certain on that. I don't have any experience with tones over a digital trunked system.

 

[clareconley]

Radio Reference shows two conventional dispatch frequencies for Rural Metro Fire under Pima County Az. 154.370 fire dispatch, and 153.815 EMS dispatch. EMS is simulcast on the fire dispatch. I have a Uniden radio and I entered the fire dispatch frequency into the fire tone out standby. I received several tone-outs for Meds units. For example Meds 845 showed tone A 1209.0 and tone B 1335.2 and Meds 874 tone A. 1209.5 and tone B 1335.6 There were several Meds calls throughout the day in Tucson and Pime County. I hope this will be helpful.

 

[prcguy]

Couple ways you can find the tone frequencies if you record them. Feed the recorded tone to an oscilloscope vertical input with variable tone generator into the horizontal input and adjust for a Lissajous pattern then the tone generator will be at the same frequency. Or if you have a frequency counter that will go down to audio you can use an audio program like Audacity to cut and paste the short recording into a long one so the audio frequency counter will lock on it.

 

[kf8yk]

For example Meds 845 showed tone A 1209.0 and tone B 1335.2 and Meds 874 tone A. 1209.5 and tone B 1335.6

Tones will not be a few tenths of a Hz different, 1209.0 and 1209.5 is the same pager tone, the display difference is just small decode errors in the scanner.

Here’s a chart with many of the standard pager tone frequencies: https://www.sigidwiki.com/images/f/f3/Tone-signaling-charts.pdf Motorola Quick Call 2 is probably the most common with GE type 99 and Plectron tones less common.

Try to match up what the scanner decodes to the closest match from this chart. Keep in mind the tone tolerance is around 1 to 2% so a scanner decode of 1209 could be +\- 12 to 25 Hz.

 

[KC1ART]

Couple ways you can find the tone frequencies if you record them. Feed the recorded tone to an oscilloscope vertical input with variable tone generator into the horizontal input and adjust for a Lissajous pattern then the tone generator will be at the same frequency. Or if you have a frequency counter that will go down to audio you can use an audio program like Audacity to cut and paste the short recording into a long one so the audio frequency counter will lock on it.

If you have Audacity, you can just highlight the tone segment, then go to Analyze -> Plot Spectrum.
The highest peak will be your tone.

 

[prcguy]

If you have Audacity, you can just highlight the tone segment, then go to Analyze -> Plot Spectrum.
The highest peak will be your tone.

View attachment 187712

That will get you into the ball park but I don't think its going to be accurate to the needed 0.1Hz resolution.

 

[EAFrizzle]

A guitar tuner works.

 

[rdmcvicar]

Where do the tones in question play?

We're not talking about PCWIN 13003, right? (Where I hear two, brief, DTMF tones prior to dispatches.)

 

[prcguy]

A guitar tuner works.

Yes, if you want to see how many cents you are off key of a musical note. I've not seen a guitar tuner that reads out frequency. A frequency counter will do it but it will usually need several seconds to lock on at audio frequencies. The tones are probably not broadest long enough for a frequency counter to lock and that's why I mentioned you may have to record it with something like Audacity then make a few copies and paste them to make a longer sample for a frequency counter to lock.

My early jobs in two way radio in the 1970s also involved troubleshooting pagers and other things with two tone and I found my ways of measuring them to make sure both the paging transmitter encoder and pager decoders were working properly. Not my first two tone rodeo.

 

[EAFrizzle]

What??? Every guitar tuner I've ever had has read out in Hz, that's how you get to concert pitch. Cents and Hertz aren't even the same kind of measurement. Cents aren't used by working musicians so much as they're used by music technicians like piano tuners and such.

 

[prcguy]

What??? Every guitar tuner I've ever had has read out in Hz, that's how you get to concert pitch. Cents and Hertz aren't even the same kind of measurement. Cents aren't used by working musicians so much as they're used by music technicians like piano tuners and such.

I have several guitar tuners here and they all read out the note like E, A, D, G, B, E, then how far off you are. Any guitar players out there that have seen a tuner that reads exact audio frequency? And to Frischizzle. have you memorized all the exact audio frequencies for all notes so you know when your guitar is tuned?

 

[prcguy]

And I do remember someone made and offered a computer program that would decode common two tone frequencies fed to your sound card. That was many years ago but it should exist somewhere.

 

[EAFrizzle]

Yeah, those don't work when you play with orchestras and wind sections. Does "A" = 440, 439, or 442? Or are you a singer-songwriter that likes to slide A down to 432 to ease up on the vocal cords a bit?

 

[prcguy]

Aaah, here is one. ComTekk Two-Tone Decoder