DESCRAMBLERS: A couple of questions please

Speech Inversion Descramblers:

They are passe now, but was wondering please....when were they first sold to consumers? and were they actually able to unscramble all the different forms of speech inversion??? The ads for them in online back issues of Popular Electronics look like they were simple plug and play...

There is a form of inversion where the base frequency that the audio is inverted around hops around. I don't think that those types were unscrambled by those kits. Otherwise, for simple voice inversion, they worked. No idea how long they were around. Pretty simple circuit.

It worked on rollong code voice inversion at least the couple I have played with did. I think I had the Ramsey Descrambler kit it was just a black box with in and outputs and a power option 9 volt or wall wart I believe also it had a couple of buttons on the front to scramble or descramble voice comms also the aor8200 came with the voice inversion card which also worked on rollong code but not as well as the Ramsey Kit.

Sent from my SM-N910V using Tapatalk

The Ramsey kit used an MX-COM MX-114 dual channel single split point inverter marketed for cordless phones and used only one voice path if I recall correctly. It was useless against Transcrypt/International variable rotating and moving split point systems as UPMan mentioned but it did work well on fixed systems. You could use different crystals to vary the split point as well.

I have a book of their products but this is a link to the earlier one that lists the single voice path MX-014 and describes how they work.
http://bitsavers.trailing-edge.com/components/mxcom/1994_MXCOM_Mixed_Signal_ICs.pdf
I think they were sold to CML Micro.

They don't work on true rolling code. Some of the simple rollers were just a few Hz off the split point and could be understood but the more secure Transcrypt products used multiple split points that slid and jumped.

As for the variable systems we just now retired our SC-460 variable system now that Transcrypt is long out of business. They are neat boards though and really well thought out. A modem box connects to a PC and a radio similar to a ham radio TNC and you send it commands using a terminal emulator. The security codes and other parameters can be changed in the field wirelessly. I've reprogrammed other agency boards over their repeaters from another county.

Generally those descramblers were set at a fixed inversion point which was usually around 3-3.3KHz

Most fixed inversion scramblers use an inversion point between 2.6 - 4.1KHz. The rolling code scramblers would hop or sweep through this range at varying speeds depending on the scrambler.

The downfall of analog inversion, be it fixed or rolling code, is they fail to break the cadence and properties of speech.

Ill have to look later tonight but I believe the aor8200 with the inversion card would quickly scan inversion points when rolling code was in use whether it was modified or not to do so I dont remember but I have an agency near me that uses rolling code still and my aor was working on it last summer we will have to see this year. I have a couple of XPR7550 radios with voice inversion options I will have to do some investigating when I get the chance.

Sent from my SM-N910V using Tapatalk

I have a Ramsey SS70 in my junk box waiting on a project. It works but I have no use for it, so I’m waiting on a chance to recycle it

The first one I saw was in 1973.

rbrtklamp2 said:

Ill have to look later tonight but I believe the aor8200 with the inversion card would quickly scan inversion points when rolling code was in use whether it was modified or not

Click to expand...

No, you have to set its frequency manually to a fixed frequency. I once looked at the inside of the card and it was a standard $5 chip that the 8200 controlled. If you had the plastic box and can make a one sided circuit board, you would only spend that $5 instead of the $100 asking price.

The rolling code voice inversion systems sends out an encrypted value what frequency the inversion circuit should use and you would need to have that value to be able to determine how to tune the voice inverse frequency. It's not a secure system as you can record the audio and then manually tune to each section of audio until you get it right and then record the output and paste together to a continuos audio stream.

/Ubbe

Speech inversion

Archie said:

Speech Inversion Descramblers:

They are passe now, but was wondering please....when were they first sold to consumers? and were they actually able to unscramble all the different forms of speech inversion??? The ads for them in online back issues of Popular Electronics look like they were simple plug and play...

Click to expand...

Don't mix the terms "scrambling" with "inversion". The devices you speak of never re-arranged anything, and therefore did not scramble. They do indeed "invert" the audio spectrum from some frequency. I have both hardware and software which does this. Every now and then I'll encounter a signal that has been "inverted" and haven't had trouble being able to listen in.

In this digital age, analog voice inversion is not used nearly as much anymore. It is used in a few locations, however, here in Arkansas. In Batesville, Arkansas the local PD uses simple voice inversion which is easily broken. The sheriff's department uses the same system for its "private" channel.

I have seen a few rural middle of nowhere agencies using older portables use it for simplex private chit chat. I was surprised what is still around with them old inversion units in field.

I have checked out a few sites over the years looking for audio clips of what old analog scrambling/inversion/encryption sounded like and had little luck. can anyone point me in the right direction?

i live near a prison that is using one of the inversion types, i assume based on sounding similar to what some motorola gmrs inversion radios sound like, and just always been curious what kind of dinosaurs they use there. i just have nothing to compare it to though

thanks

https://youtu.be/OPy_1rm940s.

The early ones simply inverted the speech spectrum. The technology goes back to the days of vacuum tubes. In about 1981 I had one of my co workers (salesman) call me from Iowa saying that his customer was complaining of "Martians" on his channel. I urged him to send me a tape and the frequency being used. A week later I play the tape and it is a rolling code speech scrambler, Transcript, if I recall. It was the most bizarre thing to hear. So I look up the frequency and find that it is shared with Iowa Beef Processors. I soon figured out they were using the scramblers to conceal bid prices for cattle lots they were bidding on.

RFI-EMI-GUY said:

The early ones simply inverted the speech spectrum. The technology goes back to the days of vacuum tubes. In about 1981 I had one of my co workers (salesman) call me from Iowa saying that his customer was complaining of "Martians" on his channel. I urged him to send me a tape and the frequency being used. A week later I play the tape and it is a rolling code speech scrambler, Transcript, if I recall. It was the most bizarre thing to hear. So I look up the frequency and find that it is shared with Iowa Beef Processors. I soon figured out they were using the scramblers to conceal bid prices for cattle lots they were bidding on.

Click to expand...

I should clarify that what was used was a time division bucket brigade type scrambler. What is heard are snippets of speech shuffled in time. So it sounds like human speech but very foreign and mechanical.

Sent from my SM-T350 using Tapatalk

wbswetnam said:

In this digital age, analog voice inversion is not used nearly as much anymore. It is used in a few locations, however, here in Arkansas. In Batesville, Arkansas the local PD uses simple voice inversion which is easily broken. The sheriff's department uses the same system for its "private" channel.

Click to expand...

Butler County MO sheriff's department uses voice inversion this way too.

N0UDG said:

Butler County MO sheriff's department uses voice inversion this way too.

Click to expand...

You can add the Perry county sheriff's department and the White county sheriff's department, both in Arkansas, for occasional "secure" use.

spacellamaman said:

I have checked out a few sites over the years looking for audio clips of what old analog scrambling/inversion/encryption sounded like and had little luck. can anyone point me in the right direction?

i live near a prison that is using one of the inversion types, i assume based on sounding similar to what some motorola gmrs inversion radios sound like, and just always been curious what kind of dinosaurs they use there. i just have nothing to compare it to though

thanks

Click to expand...

Tune an upper-sideband HF signal as lower-sideband or a lower-sideband HF signal as upper-sideband and you can hear exactly how it works. Also, note there are PC programs that will encode or decode voice inversion (the procedure is identical). For example
IZ8BLY MT63 terminal for windows and soundcards
and also note that in the US, there a legalities regarding the doing of this.

UPMan said:

There is a form of inversion where the base frequency that the audio is inverted around hops around. I don't think that those types were unscrambled by those kits. Otherwise, for simple voice inversion, they worked. No idea how long they were around. Pretty simple circuit.

Click to expand...

Paul:

As I recall didn't Uniden market a GMRS walkie-talkie with voice scrambling awhile back? Possible Midland also?