PRO 97 Help Needed

[btritch]

Can anyone tell me what the CTCSS and DCS tones and setting are for on the PRO 97 and what they're used for? Fire paging tones? I just got it today and I"m not sure I understand the book instructions.. Can anyone please explaing the CTCSS and DCS settings? Thanks!

 

[KE5BCP]

Can anyone tell me what the CTCSS and DCS tones and setting are for on the PRO 97 and what they're used for? Fire paging tones? I just got it today and I"m not sure I understand the book instructions.. Can anyone please explaing the CTCSS and DCS settings? Thanks!

Beginning on page 21 of the pdf manual:

"CTCSS (CT) mode
CTCSS mode sets the scanner to receive transmissions
using frequency modulation (FM) with Continuous Tone
Coded Squelch System (CTCSS) subaudible tone codes.
CTCSS allows multiple users to share a single radio
frequency without hearing each other’s transmissions. In
your PRO-97 scanner, the CTCSS feature can be used to
block the reception of transmissions on shared channel to
only those that use the CTCSS mode also features a Code
Search setting that allows you to instantly display and store
unknown codes into the channel memory. CTCSS tones can
sometimes be heard as a low “hum” in the background of a
voice transmission."

DCS (DC) mode
DCS mode sets the scanner to receive transmissions using
frequency modulation (FM) with Digital Coded Squelch
(DCS) subaudible data signaling. DCS is very similar to
CTCSS, except that a digital code is transmitted instead of
an audio tone. Like CTCSS, DCS allows multiple users to
share a single radio frequency without hearing each other’s
transmissions. In your PRO-97 scanner, the DCS feature
be used to block the reception of transmissions on a shared
channel to only those that use the DCS tone that you have
specifi ed. DCS mode also features a Code Search setting
that allows you to instantly display and store unknown
codes into the channel memory. DCS data can sometimes
be heard as a low “purring” sound in the background of
voice transmission. Some DCS systems transmit a special
“turn off code” at the end of each transmission. The turn
code causes a properly equipped receiver to mute before
the transmission ends, eliminating the “squelch tail” burst
noise the commonly occurs when the signal is lost."

Also see the wiki:
http://wiki.radioreference.com/index.php/Continuous_Tone-Coded_Squelch_System
http://wiki.radioreference.com/index.php/DCS

 

[btritch]

So if I have say two fire departments that share a frequency, the If I knew the CTCSS tone I could block one of them.... I see, So on the database on the pages with the county frequencies what are the columns that say tone and then they have a number and PL, is that what I'm looking for? Please explain... thanks!

 

[btritch]

Ok, I have two departmets here sharing a frequency, I heard one of them today and entered the CTPL tone and I can still hear both Fire Departments still. Is this because they are using the same PL tone? Also, I was watching the NOAA frequency for my area earlier and it jumps to different codes, Is this for different counties?? Please Help! Confused here! What's the purpose of PL CT codes if they're still going to let both departments through.

 

[KE5BCP]

What is the system you are trying to listen to with the tones?
(Please provide a link to the database here on RR)

 

[btritch]

Ok, It's right here: http://www.radioreference.com/apps/db/?ctid=135 The one I'm talking about is 154-445, It ONLY says LAFE FD, That's because Lafe FD owns the repeater, It's shared by Marmaduke, Northeast, and Delaplaine also. Wouldn't each one have a different PL tone as far as Pager tones and such go?

Hope This Helps! I Look Forward To Your Help! Thanks Again!

Brian

 

[KE5BCP]

According to the database, there is no tone used on that repeater (CSQ).

You can put your scanner into "search" mode (CT or DC without entering a tone) to see if one or more tones are being used, but so far no data has been submitted to say so.

 

[btritch]

I'm not sure about the lafe side but I did fine out today that the marmaduke side is using 173.8 so I guess when Lafe or Delaplaine Key up if it's different tone then it'll show it, If not and it's the same then that's the only one associated with it apparently, Correct?

Then how do they get the private settings on their pages? I thought that was the PL tone...I know they have them, I've had one on this freq. before

 

[wrr20891]

I'm not in Greene County, but in general, each Fire Department probably has their own set of tones to activate the pagers for their Department. The pager will ignore the tones for other Fire Departments, it just listens for the correct set. So the PL doesn't matter for pagers. Matter of fact, some transmitters disable the PL tone when transmitting pager tones so the tone frequencies won't mix with the PL tone and send out an incorrect tone. The PL tones are set when the pager is ordered/programmed.

You'll just have to listen to see if each department uses a different PL tone when using the repeater. Some rural fire departments I listen to that are using the same repeater all use the same PL tone. As above, it doesn't matter for their pagers and they want to be able to monitor what the other departments are doing for mutual aid purposes.

 

[btritch]

I see, Which county are you in? I probably have it covered, I have about half the state programmed, LOL

 

[btritch]

What Exactly Do the DCS and PL tones do anyways? I mean what's the point? I've saw the explanations on them but They're over my head. Is it for instance Baxter and Lawrence Counties using the same SO frequency to use different PL tones to keep from interferring? Is that it
?
I'm still confused on that..

 

[wrr20891]

Basically, PL and DCS tones keeps the radio speaker from opening during a transmission that does not have the proper tone. It doesn't really keep anything 'private', as the radios usually have a button to disable the PL and taking the microphone off the hook to make a transmission usually disables the PL circuit. But yes, it allows Baxter and Lawrence to use the same frequency without having to listen to each others transmissions all day long. We as scanner listeners might think it's neat to listen to, but it can be distracting to the people who use the system for work every day.

It's especially useful on VHF high band, where the repeater input for one agency might just happen to be the base or repeater output frequency of another agency several counties away. The tones allow more efficient use of the radio frequencies instead of having to increase the distance between users to make sure they don't usually interfer.

 

[btritch]

That explains it better. Thanks, I was entering the local fire frequency tonight and we use 173.8 and before I could get that entered I picked up butler co poplar bluff missouri on the same frequency. They are using the tone 167.9 so I have entered the frequency twice with their pl tone on one and mine on the other so I could name the departments. I can hear them on the 167 but not on the 173. Now between that and you're explanation I know what they are for. Now what is the difference between The ctcss and dcs's. One for voice and one for data the way I understand it? Is that right?

 

[wrr20891]

I'm not real sure about data systems (never really monitored one), but voice systems often use DCS. Originally there were just PL tones, but the total number of available tones are somewhat limited (around 51). DCS provides about 106 different choices, so it helps eliminate the possibility that another agency on the same frequency is using the same one. A lot of newer voice systems seem to use the DCS, but it may just depend on whoever designs the radio system.

This link lists the PL tones and the DCS, you can see there is more than twice the number of DCS vs PL. Scroll down to the bottom the see them.
http://www.com-spec.com/tp3200.htm

Edit: Actually, I guess CTCSS is the correct term. PL stands for Private Line, which was what Motorola called their CTCSS equipped radios. GE and RCA had other names for their CTCSS systems (names which escape me right now).

 

[btritch]

I see, so there's really no difference in pl or ct and dc tones, they're pretty well the samething in other words. OK, that makes it better to understand! And NOW I know what they're for too! Yay! Thanks!