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Pro 96/Pro 197 Digital trunking scanners
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Gary Lyon
Posted 9/30/2010 00:51 (#1379012)
Subject: Pro 96/Pro 197 Digital trunking scanners

Southeast Wyoming

I see a thread from February about police scanners:

Do any of you have a good source of information on the details of how the trunking works.  A neighbor and I have been messing with radios for years but this trunking thing is a whole new ball game; our radio tech does not understand it.  I've been reading up on the Radio Shack Pro 96 and the Pro 197.  I've printed up the WY info from (RR) but I do not understand what all is involved.  The Pro 96 documentation calls for "fleet maps" but I see no information for those on RR.

I've read so much I've lost track of it all.  Can I simply enter the control frequencies without the Talk Groups (TG) and Fleet Maps (FM), or do I need to enter TG info?  What about FM info?

I understand the trunking uses subaudible tones such as the CTCSS tones.  Is that what the HEX and DEC entries are all about?

I also see "multi-tables" with Low & High channels, channel offsets, khz steps and base frequencies.  Is it necessary to enter those multi-tables or will the scanner glean that information from the control frequency transmissions?

The email button should work; this will take more "educating" than probably should be done here on NAT.


Edited by Gary Lyon 9/30/2010 00:52
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Mike Shimek
Posted 9/30/2010 07:43 (#1379133 - in reply to #1379012)
Subject: Re: Pro 96/Pro 197 Digital trunking scanners

High Springs, Florida
Maybe I can help some, Gary. I know quite a bit about trunked radio, since I have been working in that field for over 25 years. I'll try and start simple.

I'll stick to Motorola systems as that is what I know and currently maintain.

A "Trunked Radio System" can be made up with as little as 3 RF channels or 28 RFchannels, depending on the needs of the customer. When I say "RF channels" I mean actual frequencies with a transmitter/receiver on them. "Talkgroup" is a group of radios assigned to a specific frequency or channel by the controller, i.e., "Police 1" or "Fire 1".

So what happens is this, all IDLE radios on the system are listening to the control channel. When a call is initiated on the talkgroup that the radio talkgroup selector is on, all radios on that talkgroup are assigned an RF channel, and go to that channel. All units assigned will hear the voice radio traffic. Other units on different talkgroups will not. After all traffic is completed, after a few seconds the radios return to idle and are listening to the control channel for further assignments.

Now, Fleetmaps and such. There are 3 types of Motorola trunking Type 1, Type II and Type IIi.

In a Type 1 system you have Fleets and Subfleets. (subfleet = talkgroup) The Fleets have "size codes". The size code tells you how many radios and
subfleets you can have.
For example a "Size Code M" fleet is 1025 radios in 15 subfleets.

In a Type II system there are no fleets and subleets, just talkgroups. 65535 radios in 4096 talkgroups.
The system I manage has about 3000 radios in 200 talkgroups.

In a Type IIi system you have both Type 1 and Type II talkgroups, fleets and subfleets.

The subaudible or "connect tone" is system specific. There is just one tone.

The HEX and DEC are the talkgroup numbers for Type II. For example Fire 1 talkgroup number in decimal is 2101 and in hex it is 835. Calculator in Windows will do conversions if you need them.

In a Type 1 system, it's fleet and subfleet, for example "000-1" or "200-3".

As far as programming your scanner, I am not familiar with that particular scanner. You need specific information on the trunking system you wish to monitor to program the scanner. should have it.

Any other questions fire away, I hope this helps.

Edited by Mike Shimek 9/30/2010 07:54
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Posted 9/30/2010 17:53 (#1379670 - in reply to #1379012)
Subject: RE: Pro 96/Pro 197 Digital trunking scanners

I'll try to elaborate on what Mike said. With a conventional radio system, each channel has it's own frequency. For example, the county sheriff may have a dispatch channel, a tac channel (or several of them), the town police may have a channel or two, fire may have a dispatch channel and one or more tac channels. The building official may have a channel, as well as other county departments. As I mentioned, each one has its own frequency. During the evening, the building official's channel probably isn't used, but the public safety channels may be very busy. Trunking allows for a more efficient use of the frequencies. What trunking does is to put all of the frequencies into a pool, and a computer assigns a radio one of the frequencies when it is needed and all of the frequencies are shared by the system. The frequencies are assigned randomly, so for example, on fire dispatch, when the radio is keyed one time it will be using one frequency, but the next time it may be another one. The system can have a number of talkgroups, i.e., Fire Dispatch, Tac 1, Tac 2, etc., just like in a conventional system, however they are not limited to a certain number of talkgroups because they only have "x" amount of frequecies.

My suggestion would be to purchase some software, if you don't already have it, which makes it a lot easier to program the scanner. You can even download the trunked system from the Radio Reference site if you subscribe, which isn't much. I did that last year and I don't remember what I paid for a several month subscription, but it wasn't much. If you go to, they have several different programs you can purchase and download for a nominal cost.
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Gary Lyon
Posted 10/1/2010 01:55 (#1380257 - in reply to #1379670)
Subject: RE: Pro 96/Pro 197 Digital trunking scanners

Southeast Wyoming

Thank you both.  I do have the Win96 software for the Pro 96 and I'm making a list of software for the Pro 197, I believe the neighbor wants a 197.  They appear to offer the software for a free trial period; we are busy with planting, haying and preparing for hauling beets.  I hope to have my head around some of this so I can give them a good trial with adequate time to look them over.

I think the RR membership is $15 for 180 days.  I hope to try out loading directly from there somewhere down the road.

Mike, I really appreciate the "nuts and bolts"; that is the sort of information I'm looking for.  I want to understand the mechanics of what makes it work.  I imagined a different tone for each talk group.  I'll have a lot of questions as I try to digest this.

Wyoming has a new WyoLink Project 25 Phase system - Voice System "APCO-25 Common Air Interface Exclusive".  They have gone with vhf frequencies.  I had a guy on RR email me a file for WyoLink.  There are a number of banks (county by county) of WyoLink frequencies but the talkgroup ids appear to be identical in each bank.  I wonder it each county identifies their talkgroups the same way.

I also want to program in NE, CO and KS systems and the neighbor runs into Oklahoma.  I know CO is in the 8XX.XXXX range, the others are probably each different.

So much to learn and so little time . . . 

Thanks again.  I'm sure I will be asking more questions as time allows.

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Posted 11/30/2010 05:26 (#1460834 - in reply to #1379133)
Subject: Re: Pro 96 Digital trunking scanner

I noticed that you are familiar with Trunked Radio Systems? I have a Radio Shack Pro-96 Digital Police Scanner, I am attempting to monitor Offutt Airforce Base. The base frequency is: 406.0, Offset: 380, Step: 12.5 and the signal is a strong 70% or higher. Here's my problem, I can see the I.D's showing up my display, but I am unable to hear audio/voice. If you are able to help me figure this out, it would must appreciated, Thank You! 73's to you and yours & God Bless!

-Here is the link to the website:
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