[TrunkCom] RE:status bit functions on first generation trunktrackers

[Parlini, Flash]

 Set "S1" for each block.  The decimal codes you're used to will change,
but it will work fine.  See below for an old message (1998) about this.
	Enjoy!
	  Flash

------------------------------------------------------------------------
------------------------------------------------------------------------
----

If you take the decimal (Type II) Trunk Tracker ID and convert to
binary, there are sixteen bits.  The last (least significant) four bits
are unnecessarily used by the Trunk Tracker in differentiating talk
groups, to the great consternation of most of us.  Old news, but here's
how to bypass them properly:

( I apologize if this gets too deep)

We want to break up (parse) the sixteen bits in a different manner so
that TT will ignore the last four.  Look at a Type I system:  it has
Block, Fleet, Subfleet, and Unit ID.  The TT only scans by Block, Fleet
and Subfleet  --  the Unit ID is ignored.  So we want to set up a system
where the last four bits are defined as Unit ID.  Four bits is sixteen
IDs, which is a "Size S-1" in Uniden terms.

In the S-1 parsing, the first three bits are the Block, the next seven
are the Fleet, the next two the Subfleet, and the last four are Unit ID.
The "Fleets" and "Subfleets" will have no bearing on the actual using
agencies, like they would on a real Type I system, they're just
arbitrary numbers that we can use in programming.

Note that Uniden claims S-1 has 128 Fleets, but their operating guide
only shows two digits for displaying the Fleet.  The radio actually
displays and uses three-digit Fleets just fine, from 000-0 up to 7127-3.

The following pseudo-code can be used to convert from decimal (Type II)
IDs to S-1 values.  The vertical bar character (   |   ) indicates
cocatenation.  The  "if  then  else"  construction is used to insert a
leading zero for Fleet values below ten, to match the TT display.

if (int(mod([TalkGrpID],8192)/64)>9 ) 
    then
str(int([TalkGrpID]/8192)) | str(int(mod([TalkGrpID],8192)/64))
|"-"|str(int( mod( ([TalkGrpID]/16), 4)))
    else
str(int([TalkGrpID]/8192)) |"0"| str(int(mod([TalkGrpID],8192)/64))
|"-"|str(int( mod( ([TalkGrpID]/16), 4)))

There is, of course, a catch:  you have to reprogram the scanner.  For
whatever reason, when you load a Type I identifier into the 235, it
stores it with the "ignored" bits set to "1111".  In other words, you
could load all 16 variations of your talk group into memory in "E2"
mode, but only one of those would work when you changed to "E1/ S1". 

If you have the Type II value in memory, and change the setup from "E2"
to "E1", you'll see the correct Type I ident, but it won't work.  If you
enter the same Type I ident in the next slot, then change the scanner
back to "E2", the second channel will be 15 (decimal) higher than the
original.

To work around this, you can either add 15 to all your Type II idents
ahead of time, or just change to "E1", then go through every channel and
re-enter the Type I value exactly as it appears.


-----Original Message-----
From: Brian J Cathcart [mailto:scannerdude at juno.com] 
Sent: Friday, 21 October, 2005 13:27
To: trunkcom at mailman.qth.net
Subject: Re: [TrunkCom] status bit functions on the newer Uniden
scanners

On Fri, 21 Oct 2005 08:06:50 -0400 "DB Nicholson"
<d_nicholson at bellsouth.net> writes:
> Is there a way to turn of the status bit on an 895? 

Yes and no.  No, when set to Type 2 you have to scan the status bit
talkgroup.  Yes, set the system up as a Type 1 with a custom fleetmap
set
to size code "S6" (I think) on all blocks.  It's been so long since I've
done this that I can't remember for sure on the size code.

--

The Scanner Dude
Brian J. Cathcart - KE4PMJ
South Florida Frequency & Trunking Guide - 9th Edition
Available in both Printed and CD-ROM format
http://www.scannerdude.com
_______________________________________________
TrunkCom mailing list
mailto:TrunkCom at mailman.qth.net
http://mailman.qth.net/mailman/listinfo/trunkcom

Mailman: User Guide for List Subscribers
http://mailman.qth.net/subscribers.htm