STARS "Busy Signal"

[djm]

I'm relatively new to Virginia and started monitoring STARS a few months ago after purchasing a PSR-800. Last night during the 1800 hour I heard a "busy signal" (same as you'd hear on a phone) during one side of a conversation. What's that about?

VSP had several units responding to a call in Orange Co for what sounded like a situation involving a barricaded subject. I heard a trooper on the scene coordinating the response of several other troopers on VSP Culpeper TAC Team 2 (Cul TacT). I heard both sides of the conversations from virtually all VSP responders except at least one. In that case, the on scene commander transmission was fine, but for the responder, all I heard was the "busy" tone.

I see in the db that Cul TacT has the comment "some encryption." I suppose that could be what I heard, but isn't it unusual that only one side would be encrypted? Any other ideas?

Thanks.

 

[robschonk]

The busy signal on a PSR-800 means encryption. You have an option in the software to just have silence with an encryped signal, or listen to donald duck.

 

[kc4jgc]

Wirelessly posted (SAMSUNG-SGH-T459/T459UVIA1 NetFront/3.4 Profile/MIDP-2.0 Configuration/CLDC-1.1)

On the topic of one sided encryption, it doesn't seem to be unusual at all. On the Williamsburg/James City/York/Poquoson/Gloucester system, all PD dispatchers are in the clear, but the officers are all encrypted. Even W&M campus PD is setup this way. I've also heard other one sided encryption on other systems.

 

[mike_s104]

I'm relatively new to Virginia and started monitoring STARS a few months ago after purchasing a PSR-800. Last night during the 1800 hour I heard a "busy signal" (same as you'd hear on a phone) during one side of a conversation. What's that about?

VSP had several units responding to a call in Orange Co for what sounded like a situation involving a barricaded subject. I heard a trooper on the scene coordinating the response of several other troopers on VSP Culpeper TAC Team 2 (Cul TacT). I heard both sides of the conversations from virtually all VSP responders except at least one. In that case, the on scene commander transmission was fine, but for the responder, all I heard was the "busy" tone.

I see in the db that Cul TacT has the comment "some encryption." I suppose that could be what I heard, but isn't it unusual that only one side would be encrypted? Any other ideas?

Thanks.

They all appear/seem to have the ability to encrypt but not all do. I think there are a few (radios or troopers) that have it turned on all the time either on purpose (too paranoid) or accidentally. I've heard it more frequent on the Culpeper TGs. Since they all seem to have the ability to encrypt, they are able to decrypt as well.

 

[John]

I think of it as a dual mode receive. If a users radio has the ability and proper codes to operate encrypted his/her radio will properly receive the encrypted transmissions whether they have encryption turned on or not. So if trooper A turns on encrytion but trooper B doesn't, B will still hear everything A says just fine. However when B talks back they will be in the clear since they did not turn on encryption only A did.

It a lot of ways this makes encryption much less effective. If only one side of a conversation is encrypted then a lot of the content can be deduced from the other parts that are not. The ability of users to selectively turn encryption on and off is one of the big vulnerabilities. That's why you see systems that truly have sensitive communications leaving encryption turned on all the time for everyone at least on selected channels.

John