Had an inquiry about my video PoC on youtube with MDC1200 on app_rpt, and
thought it might be of interest to the list. I'm a hack, not a good
programer, but I can read and write protocols 
Does anyone use MDC with app_rpt, and want to improve it?
The original inquiry and my response is below.
Hi Bryan!
I found your video on Youtube (link
<https://www.youtube.com/watch?v=MgdaXkD8Dtk>\). I have app_rpt running now on
my system (fresh install using DIAL linux, link <https://allstarlink.org/> and
link <http://ohnosec.org/drupal/node/198>\). I have the MDC-1200 functionality
complied and working. I can encode and decode packets successfully, which is
excellent.One thing I've noticed is that the app_rpt MDC-1200 functionality seems on
only include options for Call, Emergency, Status, and ID - but not
Stun/Un-Stun. In your video, you demonstrate Stun and Un-Stun capabilities.
Mind if I ask how this was accomplished? Did you just customize the code to
add this, or do I have the wrong version of the code?Any assistance you can provide would be great. If you did modify the
libraries, and don't mind sharing, can you send a link to where I can find them?
It's GPL, it's a requirement to share. I'm to lazy to make diffs 
I added the following in app_rpt.c : line 24883 or so
else if (p->type[0] == 'K') // kill a unit
{
mdc_encoder_set_packet(ps->mdc,0x22b,0x00,p->UnitID);
}
else if (p->type[0] == 'U') // UnKill a unit
{
mdc_encoder_set_packet(ps->mdc,0x2b,0x0c,p->UnitID);
Now in the logging/monitor part: line 20596 or so
/* if for Stun ACK */
if ((op == 0x0b) && (arg == 0x00))
{
myrpt->lastunit = unitID;
sprintf(ustr,"STUN ACK %04X",unitID);
#ifdef _MDC_ENCODE_H_
mdc1200_ack_status(myrpt,unitID);
#endif
mdc1200_notify(myrpt,NULL,ustr);
mdc1200_send(myrpt,ustr);
mdc1200_cmd(myrpt,ustr);
}}
What needs to be done is to setup a verification of the MDC commands.
When you stun a unit it ACK's to say it's stunned. This needs to tie into a
verification procedure on the K command, where it keeps trying to stun the
unit until it has an ACK. I'm not sure how to do this. Second this needs to
be tied into the repeater with an over the air response like "UNITNNNN KILLED".
rpt cmd 40821 cop 60 K,b055 is the command that will stun unit b055
rpt cmd 40821 cop 60 U,b055 is the command that will stun unit b055
I need to figure out how to make this work from over the air input, but that
might be dangerous unless we have a verification loop built in. A misread
DTMF digit could kill the wrong radio.
73's
···
On 12/11/15 12:46 AM, Brett Woollum wrote:
--
Bryan Fields, W9CR
Florida Simulcast Group, Inc.
--
Bryan Fields
727-409-1194 - Voice
727-214-2508 - Fax
http://bryanfields.net