Various EDACS questions

[lwvmobile]

Hello all,

Just had a few questions about EDACS and its variants, see if anybody knows or has observed any of these in particular.

1. EDACS ESK with Extended Adressing has MT-1 status values in its patent sheet of 00001 for a TDMA channel? Has this ever been observed in any working system out there? In a previous thread where I was asking around for, @EricCottrell had posted that the command 0xA8 (0x08 after XOR) would have been the command for this type of channel. Just wandered if this was ever observed in a working system. I have implemented it in my software more out of curiosity, and very occassionally, I will get this, but the LCN is usually something out of the system like 17 or 25. Perhaps I wasn't looking at the right part of the frames to get one, or maybe its more of a logical channel and not an actual RF channel. Any thought? Same for Analog and Group Data, both having commmands of 0xB0(0x10) and 0x90(0x30), I think. I only have observations based on SLERS, I don't even know if there are any other EDACS ESK with EA active in the world.

Thread from last year for anybody wanting to catch up;

EDACS / EDACS ESK Frame layout map?

I tried searching around, but I was wondering if anybody had any links or information on how EDACS and EDACS ESK control signal frames are layed out or mapped out. I found this in the wiki: https://wiki.radioreference.com/index.php/ESK#How_does_ESK_work.3F Which does a really good job at...

forums.radioreference.com

2. EDACS Networked, with or without ESK. Anybody got a general list of commands used on this type of system? In addition to 0xEE for voice, I was getting 0xEF as well as 0xF3 for voice calls, although I may be mistaken on the 0xF3, perhaps that was something else pertaining to the system. Any idea on how this type of system differentiates between digital calls and analog calls. I was using a sample provided by Lindsay of San Antonio EDACS Networks with ESK, and going through all the frame commands had a few I'd never seen. This is the system I was testing out.

San Antonio/Bexar County Trunking System, San Antonio, Texas

San Antonio/Bexar County Trunking System Profile

www.radioreference.com

3. EDACS Standard and Networked. Private Calls. During a private call, only the Sender info comes off the control channel, but if its the sender making a private call, then how does the recepient know how to answer if the data for who the call is going to isn't available. Is this correct?

Well, can't think of any more questions at the moment, but anybody wanting to weigh in might help me along with my software. Its made some progress since last year, after a 10 month or so hiatus, but trying to make it work for every single EDACS system out there is quite interesting. Maybe its just me, but perhaps every EDACS system has its own little quirks and things that are only on that particular site or system and no others out there. Am I the only one thinking that may be the case.

 

[lwvmobile]

4. EDACS Standard and Networked. Which command and what part of the frame will you find the information which relays the LCN channel the control channel is currently occupying. I can do this in Extended Addressing, but same rules don't seem to apply in standard and networked. in Extended Addressing, if you look at command 0xFC, fr_4 (message 2) it is
EDACS-ESK-EA FRAME:
FR_1=[5C07EEB 239] <-- 0xFC ^ 0xA0 = 0x5C
FR_2=[A3F8114 DC6]
FR_3=[5C07EEB 239]
FR_4=[C3CC1C1 2DC] <- 0xC1 & 0x1F = 0x1 (Control LCN = 1)
FR_5=[3C33E3E D23]
FR_6=[C3CC1C1 2DC]
if (((fr_4 >> 12) & 0x1F) != 0){
CC_LCN = ((fr_4 >> 12) & 0x1F);

EDACS-ESK Networked Frame:
FR_1=[5C282D078F]
FR_2=[A3D7D2F870]
FR_3=[5C282D078F]
FR_4=[4F30615C57] <- second message diffferent
FR_5=[B0CF9EA3A8]
FR_6=[4F30615C57]

FR_1=[5CE3368A41]
FR_2=[A31CC975BE]
FR_3=[5CE3368A41]
FR_4=[5CE3368A41] <- second message the same
FR_5=[A31CC975BE]
FR_6=[5CE3368A41]

EDACS Network Standard:
FR_1=[FC9FFFFEBA]
FR_2=[ 360000145]
FR_3=[FC9FFFFEBA]
FR_4=[FC9FFFFEB2]
FR_5=[ 360000145]
FR_6=[FC9FFFFEBA]

FR_1=[FC206003DF]
FR_2=[ 3DF9FFC20]
FR_3=[FC206003DF]
FR_4=[FC400039AD]
FR_5=[ 3BFFFC692]
FR_6=[FC400039AD]

 

[lwvmobile]

Okay, nix the questions above, I think I have a better grasp on those elements now. Switched to pure mt1 and mt2 values for Extended Addressing and that's working pretty well for me thus far. I have all the Standard/Networked things worked out fair enough as well.

A bit of a mystery to me has come up lately though, here in Florida on the Extended Addressing sites with ESK (SLERS), I have noticed a few sites have ESK on during parts of the day, and ESK disabled during parts of the day.

The question this makes me wonder is, if ESK if flipped on and off during the day, can hand held radios programmed with ESK switch over to using non ESK. The system is still Extended Addressing, just no ^0xA0 going on. I realized this several nights ago when I had a strong signal but couldn't get a proper site id, then I viewed the messages and realized they weren't using ESK. Since then, I've noticed at various times of day or night, the control channel will flip between using ESK and not using ESK.

So, does doing this disrupt service to the handhelds on a site and force them to another site, or do they have programming that allows them to use either/or on the fly?