Batboard

Hello all,

According to my knowledge, radios can only be inhibited on a Digital P25 or trunked system right? Well from what I read from this post on radio reference, a radio even on an analog or conventional system/frequency can be inhibited. Is this true?? And if so, how so??

Here's the link to the post:
http://www.radioreference.com/forums/sh ... ht=inhibit

*Any insight on this would be greatly appreciated!

In a simple answer...YES!

Radios conventional analog channels can be inhibitted as well as trunking radios.

The post over at RR is correct.......

Yup. All it takes is a couple check boxes. Although, why anyone would check them off to begin (short of being the system admin) with is beyond me...

In the MDC system setup, there's a box for "Radio Inhibit". The CPS help describes this as:

Enables the radio to receive a remote Inhibit signal while operating on the current MDC Signaling System. This inhibit signal is a shutdown command sent from the dispatcher unit. Upon receipt of this command, the radio transmits a quick acknowledgement to the dispatch equipment. The radio then goes into a dormant state during which the receiver audio is muted and the transmit audio path is blocked. While inhibited all radio-user controls are rendered inoperative; Scan mode is stopped on the operating mode/channel which received the command, and all Radio LED’s are turned off.

So, if you have that box checked in the MDC system, and the MDC system on a channel that actually uses it, there's a possibility of you're radio being inhibited.

Anyone know what the procedure for resurrecting one of these inhibited radios is? Is it the same as trunked systems, where the inhibiting console is required?

When inhibited by an MDC inhibit command "4Ah", it goes into a state called ROS-Idle. In essence, the radio can be turned on, and it will be receiving on the selected channel, but it will pass no audio, will block any transmit command, and will display nothing on the display or LEDs.

The radio can be restored by sending it, over the selected channel, the MDC command "5Ah". This can be done by any installation capable of sending advanced MDC commands; it need not be the same as the one that sent the inhibit command.

As a prior reply indicates, there is no earthly reason to enable "Radio Inhibit" in a single, privately-owned radio. This feature is for fleet operators: it prevents someone from using a purloined radio to transmit interference over the channel and it tends to eliminate the market for stolen radios. Most sophisticated PDs and FDs implement the feature.

What device is available to provide these advanced MDC commands and do you have any other info about these 4Ah and 5Ah commands, data? etc.

Without purporting to offer a complete list, certain Motorola C200 tone remote controls and properly optioned and programmed Cimarron C Plus III ANI decoder/encoders.

Kenwood also offers this via DTMF. It is very common.

RKG wrote:Most sophisticated PDs and FDs implement the feature.

This scares me greatly. What stops someone in, say, organized crime (or terrorists) from building up a list of MDC IDs on the local public safety department, buying a console on eBay, and then sending inhibit commands to all the IDs right before, say, their bank heist? It seems unlikely to me that even the best of dispatchers would realize what was going on, and even if they did, it would just be a battle to see who could send the commands faster?

Lets just hope they don't have any good radio techs on there payroll...

i've discussed this with many pd's and fd's and they concider it along the same lines as they don't see the need to have any type of security at the repeater sites where someone could just simply cut the antennae feed or damage whatever they want or no security at water treatment plants so anyone could drive right up and throw something in. from what i see from the that have to take care of the budgets, they see things like this as corrective instead of preventative. they will look into it after it happens. and not just happen somewhere else in the country, they won't worry about it until it happens to them. but back to being able to remotely shut down radios you get alot of different answers from departments on what they want to do with that option. some like it and use it how it was intended to be used but that makes them vulnerable to sabotage. others just disable that and deal with stolen radios or unauthorized use in their own ways. myself i think it's a great feature but needs to be updated, it needs to be permanently set from the factory so you can't just shut it off and it needs to have a individual code along with the individual radio id that either the factory can send out to disable radios or that only the chief or executive has access to.

fogster wrote:What stops someone in, say, organized crime (or terrorists) from building up a list of MDC IDs on the local public safety department, buying a console on eBay, and then sending inhibit commands to all the IDs right before, say, their bank heist?

Nothing. Like most things in life, inhibit capability is a double edged sword.

FWIW, you can inhibit with certain high end MDC1200-capable Icom portables nowadays.

mr.syntrx wrote:FWIW, you can inhibit with certain high end MDC1200-capable Icom portables nowadays.

Do you mean you can also inhibit certain high-end Icom radios, or you can send inhibit commands from certain Icom radios?

Both, actually.

The capabilities of their radios are described here:

http://www.icom.co.jp/world/products/pdf/MDC_1200.pdf

LuiePL wrote:Yup. All it takes is a couple check boxes. Although, why anyone would check them off to begin (short of being the system admin) with is beyond me...

For the Pro (Waris) CPS are these check boxes exactly to enable/disable a radio from being inhibited remotely? Where would you look for this if its available in the DOS based programs (HT1000, GP/GM300, Maxtrac, etc. - I know there's no check boxes in DOS of course)

I typed too fast - I meant where in the CPS do you find these check boxes - thanks.

I'm probably wrong, but I seem to remember reading somewhere you can do this with an HT1550 as well. I'm sure I'll be corrected shortly.

mr.syntrx wrote: FWIW, you can inhibit with certain high end MDC1200-capable Icom portables nowadays.

On a related note, Tait TP9100/TM9100 series radios can send conventional P25 stun messages, but that functionality is only available with a heavily restricted feature option.