APCO-25 - digital vs analog?

[Midd1994]

Okay, I've seen references that some scanners will track APCO-25 non-digital, whereas others will track APCO-25 digital. I'm trying to figure out what to buy for my first scanner, and don't want to buy analog if the local agencies are using digital.

The reference page for Bonner County, Idaho only says that the Sheriff's department uses APCO-25, but doesn't specifiy whether it's digital or analog.

Can someone enlighten me a bit, or point me to an article or posting that describes APCO-25 in some detail?

[n4voxgill]

apco is digital. It can be either trunked or conventional, but it is digital.

[Midd1994]

According to several sources I've read that the Uniden BCT-15 can pick up APCO-25, but it also says that it's only an analog unit. So that doesn't seem to mesh.

[scancapecod]

Post #2 in this thread is the correct answer. The BCT-15 does not have P25 capability. It is analog only.

[Midd1994]

Thank you. Nice to know that Radio Shack's description is bogus!


http://www.radioshack.com/product/in...&tab=techSpecs

"Follows APCO 25 digital trunking systems? -- Yes"


Oh, and the "Monitoring Times Trunked Scanner Reference Chart" (linked from the Wiki) also says the BCT-15 picks up APCO 25.
http://www.monitoringtimes.com/html/...dscanners.html

Sure makes it hard to find accurate information!

[zz0468]

The full APCO 25 specification calls for radios to be backward compatible. So, an APCO 25 compliant radio would have both digital and analog capability, with analog FM in several bandwidths. Could this be what they mean by APCO 25 analog?

I once did an interoperability project where the grant funding required APCO 25 compliant radios, but did not require APCO 25 digital operation. I bought a million dollars worth of Motorola Quantars and ran 'em 16K0F3E. It satisfied the grant requirement and, in a manner of speaking, was APCO 25 analog. Nevermind that it was just plain old FM... it DID satisfy the requirements!

[DaveNF2G]

Unfortunately for the scanner shopper, advertising copy does not always match the exact technical meaning of the terms used.

APCO Project 25 includes the P25 CAI (Common Air Interface), which is a particular way of producing digital voice transmissions that can be used in both conventional and non-P25 trunked systems, and P25 trunking with a 9600 bps control channel datastream and all P25 CAI digital talkgroups.

[N_Jay]

Originally Posted by zz0468

The full APCO 25 specification calls for radios to be backward compatible. So, an APCO 25 compliant radio would have both digital and analog capability, with analog FM in several bandwidths. Could this be what they mean by APCO 25 analog?

I once did an interoperability project where the grant funding required APCO 25 compliant radios, but did not require APCO 25 digital operation. I bought a million dollars worth of Motorola Quantars and ran 'em 16K0F3E. It satisfied the grant requirement and, in a manner of speaking, was APCO 25 analog. Nevermind that it was just plain old FM... it DID satisfy the requirements!

That is stretching a definition. You are lucky it did not get rejected.
Then again, most people reviewing grant applications are not technical.

P-25 requires backwards compatibility with analog FM, but that does not make any form of analog FM P-25!

[UPMan]

Part of the problem in conceptualizing this is that P25 is not a single thing. It is actually a suite of standards. P25 CAI is the "digital voice" standard. There is also a trunked system signalling standard. These two standards together are what most people mean when they say "APCO 25 system". However there are other parts of the suite that deal with other matters...to be fully compliant, you have to use the entire suite all applicable parts.

[zz0468]

Originally Posted by N_Jay

That is stretching a definition. You are lucky it did not get rejected.
Then again, most people reviewing grant applications are not technical.

Oh, yeah... that definitiion was stretched to the breaking point. The alternative was to build a mutual aid/interoperability system that none of the surrounding agencies was ready to talk to. It appeared that the intent of the grant was that equipment purchased would not be rendered obsolete by either refarming/narrow banding, or full APCO 25 digital implementation. With that interpretation, we were ok.

Originally Posted by N_Jay

P-25 requires backwards compatibility with analog FM, but that does not make any form of analog FM P-25!

I agree, but going back to the original post, I have to wonder if that's what he's talking about.

[N_Jay]

Originally Posted by UPMan

Part of the problem in conceptualizing this is that P25 is not a single thing. It is actually a suite of standards. P25 CAI is the "digital voice" standard. There is also a trunked system signalling standard. These two standards together are what most people mean when they say "APCO 25 system". However there are other parts of the suite that deal with other matters...to be fully compliant, you have to use the entire suite.

UpMan, good description, until the last phrase.

You only have to use all the "applicable" parts.

I.E. If you have conventional equipment it does not need to use the trunking standard.
If you have non-secure equipment, it does not have to us the encryption standards.
Etc.

[LeeBarnes]

Originally Posted by Midd1994

Thank you. Nice to know that Radio Shack's description is bogus!


http://www.radioshack.com/product/in...&tab=techSpecs

"Follows APCO 25 digital trunking systems? -- Yes"

that doesn't surprise me much, actually. as the saying goes, buyer beware.

what did surprise me is the price. way too high for what you can get it. about $230 seems to be the going rate.

[BaLa]

Originally Posted by LeeBarnes

that doesn't surprise me much, actually. as the saying goes, buyer beware.

what did surprise me is the price. way too high for what you can get it. about $230 seems to be the going rate.

Not exactly news..they've been pricing them too high since they started offering them onlne.

[scansomd]

Question for you:

If I were a government entity, interested in adding APCO 25 functionality to an existing radio system, where could I locate the APCO 25 standard? I.E, where would I find formal documentation on the standard to discuss the issue with my software / hardware engineers?

Originally Posted by UPMan

Part of the problem in conceptualizing this is that P25 is not a single thing. It is actually a suite of standards. P25 CAI is the "digital voice" standard. There is also a trunked system signalling standard. These two standards together are what most people mean when they say "APCO 25 system". However there are other parts of the suite that deal with other matters...to be fully compliant, you have to use the entire suite all applicable parts.

[UPMan]

From the IHS Standards Store. General info (not the full spec) is on APCO's Web Site. (Above references found using Google.) There is also an article with references at wikipedia.