Telephone Eavesdropping - Page 1
Forum section: electronics / projects

author: Erica
author_rank: Regular Contributor
timestamp: May 05, 2015, 10:38:14 am
content: .

author: TerraHertz
author_rank: Super Contributor
timestamp: May 05, 2015, 01:23:48 pm
content: Is the telephone an old style landline phone? Or an electronic/wireless type on a landline?Why not post a photo of the phone, and the circuit, from the start?If you have the circuit because it's on the inside of the case, it must be an old style phone."The ringer is a perfect microphone, I verified this myself"How? Not saying it's impossible, just that you said "no idea what I'm doing." So I wondered.Also what you mean by 'perfect microphone'.You bought a $300 scope to check this? That's determination. Good for you.Anyway, the line is predominantly a current loop circuit, so just looking at the voltage between the two wires with a scope won't tell you much. Also it's differential, and around 48V DC when off-hook, and may have a lot of common mode noise, so you won't be able to see any tiny signal.But there is a way, using a small transformer to convert any AC audio current signal on the line to a ground-referenced voltage signal your scope can see.Incidentally, if you have a serious reason to suspect eavesdropping, the situation can be used to your advantage. Feed them disinfo. If you see action responses, it answers your question more definitely than any measurement of signal on the wire.The funny side to this, is that mobile phones are so much more tools of eavesdropping, tracking and profiling, but most people seem to not even think about it.

author: Erica
author_rank: Regular Contributor
timestamp: May 05, 2015, 05:10:37 pm
content: .

author: David_AVD
author_rank: Super Contributor
timestamp: May 05, 2015, 09:10:04 pm
content: Yes, the piezo sounder (ringer) could be used as a microphone on its own, but not in this application.On a modern phone, the AC ring voltage from the phone line is rectified to power a dedicated ringer chip. The ringer chip then drives the piezo with the required tones. There is no real audio path from the piezo back to the line.The old Nazi story you quote would rely on the phone having a old style bell with magnetic coil. The much more likely scenarios are that the physical phone wires have been intercepted or there is an FM bug in the vicinity.

author: JBaughb
author_rank: Regular Contributor
timestamp: May 05, 2015, 09:16:51 pm
content: @Erica @TerraHertzGlad you two found each other.Nothing on the PCB makes me think its been modified or tampered with. I would second Davids comment that IF there is an eavesdropping device it would be interfacing with one of the wires down the line.Curious, what makes you think someone would be eavesdropping? Ex-lover? Employer? Government? Overbearing mother?

author: German_EE
author_rank: Super Contributor
timestamp: May 05, 2015, 09:21:37 pm
content: As somebody who has actually found a bug in his telephone (it rattled around in the case after the phone was dropped) I think that you are doing this the wrong way:1) Unplug your telephone and look underneath, does the lead plug directly into the base unit or is anything attached?2) Open the handset, is there anything inside apart from the microphone and earpiece?3) Open the base unit. Most telephones contain a single PCB so is there anything inside that could raise suspicions such as a smaller PCB connected to different parts of the phone?This covers 99,9% of cases including mine. Without modification it is impossible for a telephone to send a signal down the line with the handset in place because the circuits switch over to the bell/ringer device. The ringer is normally soldered to the pcb so modifications will be easy to spot.In my case I was living in Eastern Europe and after one of the cats knocked the phone off the table it rattled inside. Eager to fix it I opened up the base unit and found a 3cm x 2cm pcb wired across various connections including the incoming line. There were no ID marks on the two chips as the tops had been sanded off.Edit: Comments made before I saw your pictures. I do not think that this telephone has been modified.

author: Bud
author_rank: Super Contributor
timestamp: May 05, 2015, 09:30:45 pm
content: Erica,why dont you just buy a new telephone and save your money and time.

author: Bud
author_rank: Super Contributor
timestamp: May 05, 2015, 09:36:25 pm
content: Quote from: JBaughb on May 05, 2015, 09:16:51 pmand Rigol. Because ...Quote from: Erica on May 05, 2015, 10:38:14 amNeither does Rigol.

author: SArepairman
author_rank: Frequent Contributor
timestamp: May 05, 2015, 09:57:46 pm
content: you should use misinformation to have them walk into a net trap thats weighted down with all the test equipmentwhat are you even gonna do if you find a bug?i think your best bet is to use mis information to lead someone to a trap of some kind, assuming your in a free country, idk if you can win a one man war against the secret police loli thought someone could go outside your house with a linemans headset or on the power pole to eavesdrop on telephone communications, but I don't know much about these things.have you considered using a non linear junction detector ? they detect IC junctions, and multi metal junctions, which are common in circuit boards (assuming osmoene hid something in the wall or such)you can also use a time of flight reflectometer to see if there is a tap on your phone line (it's impedance will show up).And of course, good bugs can be designed to operate in bursts and whatnot, making them extremely difficult to detect.http://en.wikipedia.org/wiki/Time-domain_reflectometeralso they can make light bulbs modulate audio by blinking really fast, which can be picked up with a o-scope connected to a photo detector sensor. you cant see it but equipment can pick it up. check your lights. like soand of course checking your computers for microphones which transmit on the internet is a good idea.and cell phones with software bugs.. and computers with software bugs.. and information being modulated by your computers power supply, and using yoour monitor as a radio transmitter.. i can imagine some kind of lock in amplifier operating on power lines or something too.. hard as fuck to detect.I mean basically yo get peace of mind you need to completely rewire your house (using armored conduit thats welded) (this possibly includes metal (gas and water) pipes connected to your earth ground, and your actual earth ground, and your power pole and get 24/7 surveillance with battery/generator backup, with redundancies, and probably getting massive RF filters on your mains electricity, and sticking to encrypted communications using a computer (as your land line is easy to compromise from the street). and you probobly wanna do some custom booby traps on your survilence system for when you are not home (ones that you spend awake in bed for a week designing)... then of course parabolic microphones, laser window microphones,dont forget the barbed wire fense 300 meters around your house, guarded by men with guns... and probobly getting linear power supplies for everything in your house, to make bugs easier to detect, and shielding/filtering the ever living shit out of computers or things that its not practical to use a linear supply for. no chinese wall warts allowedthis issue is a massive head ache. i fucking hate peeping toms lol, just fuck man, you can rob me, but you seriously gotta creep that hard? i cant even stand listening to someone else talking on the telephone in the same room, idk how the hell you get the kind of people who spend their time developing this zany bullshiti think id flat out murder someone using a fucking butter knife if they made me go through all that troublei feel extremely bad for you if you are not suffering from drug psychosis. if you are then sober up, easy peasy

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 05:25:06 am
content: .

author: babysitter
author_rank: Frequent Contributor
timestamp: May 06, 2015, 05:34:58 am
content: Did you consider help outside this forum, say, a certified psychologist?This is not a "ringer" in the old way discussed as "potential microphone". Your finding that a piezo acts as microphone is absolutely normal.Buying all this stuff proves a certain degree of overacting.Todayits way easier than trying to extract something from that bloody mess of signals which might or might not be found on your phone lines. (Which is, I can tell you for certain, not - not from this phone)

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 05:37:32 am
content: .

author: tggzzz
author_rank: Super Contributor
timestamp: May 06, 2015, 06:59:42 am
content: If you do find something that you feel proves your line is being tapped, what exactly will your response be? If nothing, then why bother to do the tests in the first place?

author: JBaughb
author_rank: Regular Contributor
timestamp: May 06, 2015, 08:00:57 am
content: Oscilloscope measures voltage over a set time period. I don't see how this alone would help you in this situation. Maybe a spectrum analyzer could find some hidden signals (and if you're willing to buy one of those for this, then someone eavesdropping on your isn't your worst problem).I've heard of input and output impedance being measured with a signal generator, an oscilloscope (or something to measure AC voltage) and a variable resistor.

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 06, 2015, 08:18:53 am
content: Quote from: tggzzz on May 06, 2015, 06:59:42 amYou stop talking about certain things. The stasi were particularly effective at waiting long times to find enough evidence to lock someone up.It's probably not tapped or bugged to be honest. There is no straightforward analogue pathway and it's unlikely any existing hardware has been compromised. They would camp out somewhere and use an infra red laser bounced off any glass surfaces on the building if they wanted to listen. They make kit that even the stupidest PI or intelligence community could use these days.I worked for a company that built military surveillance products and it's really not that uncommon for things to be attached to devices and shipped to individuals etc but that's usually in a corporate capacity (think Cisco intercepts recently). It's quite scary. I walked from the company when I realised what my ethics were and that they were being compromised.However establishing cause for suspicion is step one. If you're in Belarus or certain Russian states and dissing the government, I'd be concerned for example. If you're here in the UK and are spending your spare time buying 50kg bags of industrial fertilizer and you're not a farmer, I'd be concerned. But Joe average, forget it; you're just nuts. If you've done something naughty, you probably shouldn't have done it or probably should have escaped somewhere where it isn't naughty first if you want to save yourself. If you're planning something naughty, think first.There are a few "modern dictatorships" still and they buy and use nefarious things but this is the 0.1% case. If you genuinely are that 0.1% case, good luck but try and hit the border first.

author: tggzzz
author_rank: Super Contributor
timestamp: May 06, 2015, 08:28:31 am
content: Quote from: smjcuk on May 06, 2015, 08:18:53 amThat's all very rational - and therefore might not be relevant to the OP.

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 06, 2015, 08:35:39 am
content: I did consider that

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 08:39:58 am
content: Quote from: smjcuk on May 06, 2015, 08:18:53 amI work for a high security government facility. This is were these phones are being used. I am not in the US.These phones are being used to monitor what the employees are saying in the offices. I believe its being done by a malicious source and is not known by executive management.

author: David_AVD
author_rank: Super Contributor
timestamp: May 06, 2015, 08:42:23 am
content: Quote from: Erica on May 06, 2015, 05:25:06 amI didn't look at any great length, but the 8 pin IC on the board is likely to be the ringer driver. If you have the official schematic for the board I could say with more certainty.Quote from: Erica on May 06, 2015, 05:25:06 amThe text linked to refers to ringer coils, not the piezo with IC driver circuit you have.I have worked with telephone circuitry over the years and have a pretty good understanding of the ringer circuitry in particular.

author: David_AVD
author_rank: Super Contributor
timestamp: May 06, 2015, 08:44:47 am
content: Quote from: Erica on May 06, 2015, 08:39:58 amThere's probably a ton of eavesdropping methods that could be used in an office environment without resorting to the phone ringer antics you're hung up on.

author: atferrari
author_rank: Frequent Contributor
timestamp: May 06, 2015, 09:00:08 am
content: Quote from: Erica on May 05, 2015, 05:10:37 pmBeasides the poor quality and pathetic music (at least for me), did it match anything that you were listening around you? If not, those allegged bad guys are tuning the wrong phone.

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 06, 2015, 09:01:23 am
content: If you work in a government facility, you're probably being recorded anyway by management as well.My grandfather used to design buildings for the MoD in the UK when he was younger. They had to make them eavesdropping proof. That included things like rubber couplers on the pipes coming in and out of the rooms as you could work out what people were typing back then based on the sounds the typewriters made.As David_AVD said, there are a million ways. Sounds like you need a less stressful job

author: JBaughb
author_rank: Regular Contributor
timestamp: May 06, 2015, 09:12:37 am
content: Quote from: Erica on May 06, 2015, 08:39:58 amIf that is the case, why not bring it up to management. I am sure that they have resourced available that are better than an electronics novice with expensive equipment getting information from a web forum. Not that we aren't all awesome here, but this does seem like the most effective way to solve the problem, if there even is a problem.

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 09:13:15 am
content: [.

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 09:20:57 am
content: l.

author: SL4P
author_rank: Super Contributor
timestamp: May 06, 2015, 09:25:11 am
content: I'm afraid of trivialising the OPs concerns, but in today's world, there are twenty more effective ways of audio bugging a room than hot-wiring a legitimate handset. And there are other bugging opportunities... video, IR etc.e.g if you have windows, check for lasers being reflected off the glass... and so many more.p.s. It can't be that 'high security', if they let staff walk in and out with personal electronic test gear tagged across installed assets!

author: Towger
author_rank: Super Contributor
timestamp: May 06, 2015, 09:26:46 am
content: Whats the fuss, is you work for the government then just assume all calls are monitored and live with it.I know someone who worked in security for a large UK defence manufacturer, during the old war years. They knew their phones were being bugged, not by the Russians or Americans but by the organisation when did more of their work for, the UK's MOD. In their opinion the MOD leaked like a sieve and you don't want your customer knowing your costs and other issues etc.

author: kjs
author_rank: Regular Contributor
timestamp: May 06, 2015, 09:33:05 am
content: Quote from: Erica on May 06, 2015, 09:13:15 amBecause your scope probe has ground on one side and the phone line is balanced. You short one side to ground with your probe. You would need a differential probe for that.

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 09:43:54 am
content: Quote from: kjs on May 06, 2015, 09:33:05 amThanks!!Can you post a link to the sort of probe I need?

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 06, 2015, 10:01:47 am
content: Quote from: Towger on May 06, 2015, 09:26:46 amDefinitely. There was a whole international uppityness that went on between a couple of large European defence company subsidiaries in the 1980s and 1990s. They weren't even sly about it. They parked fuck off great big green MoD SIGINT trucks outside the facility on the public roads around it who responded by erecting a 20 foot high solid metal fence and foiling all the windows. I worked over the road at another company then but we ate and drank in the same pub at lunch times and they were all thoroughly fed up with it all by then. Both sides of the fence that was. The pub was the neutral zone

author: LabSpokane
author_rank: Super Contributor
timestamp: May 06, 2015, 10:09:31 am
content: Quote from: Erica on May 06, 2015, 08:39:58 am*That* was important information. They're using the speakerphone capability. The mic on a office phone can be activated even while the phone is on the hook. Just disconnect your phone from the wall jack and your conversations will now be private unless another monitoring device is used. This is a very well-known capability of modern office phones and is frequently used.If you need to prove the assertion, you just need to get a copy of the manual for the PBX system. The capability is listed sometimes as "on-hook" answering or similar weasel words.Another solution for privacy I saw used to good effect was sticking a piece of gum over the microphone.For those that doubt the capability, just ask Ed Snowden.ETA: An office PBX phone is very different from a home phone. That phone is essentially always live. And activating the microphone versus the light that tells one the mic is hot are separate functions. Sadly, the surveillance functions are a key selling point to the managers who purchase the systems.The other obvious surveillance vector is malware installed on PCs that perform the same function of activating cameras and microphones surreptitiously. Taping over the camera fixes that, and you're back to gum, or physical disconnection of the internal mic on the PC.

author: tggzzz
author_rank: Super Contributor
timestamp: May 06, 2015, 10:17:45 am
content: Quote from: Erica on May 06, 2015, 08:39:58 amAh, at last the important information arises. Fundamentally, you justhaveto be joking.This is above you pay grade. Your onlyrationalcourse of action is to report your suspicions, in writing, to the relevant people - which are likely to include you line manager and the security service.if you conduct your own investigation and are discovered (e.g. by someone wondering why you are using your personal scope) modifying and investigating "highly secure" comms equipment, you will have alotof explaining to do. At the very least they will seriously question your judgement.

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 10:24:00 am
content: .

author: LabSpokane
author_rank: Super Contributor
timestamp: May 06, 2015, 10:28:42 am
content: Quote from: tggzzz on May 06, 2015, 10:17:45 amI'm not so sure this a joke. What I'm surprised about is that anyone managing a secure facility is not aware of this capability.

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 10:31:33 am
content: .

author: LabSpokane
author_rank: Super Contributor
timestamp: May 06, 2015, 10:32:36 am
content: Quote from: Erica on May 06, 2015, 10:24:00 amA private PBX can still be used to listen to telephone conversations. They are designed this way.And is it telephone conversations that are overheard or general office conversations? Depending on the phone design, the handset mic can still be hot while the phone is on the hook.

author: LabSpokane
author_rank: Super Contributor
timestamp: May 06, 2015, 10:38:28 am
content: Quote from: Erica on May 06, 2015, 10:31:33 amOnly from the side of the "eavesdroppee" as it were. From the reading I've done, I would assume that no PBX phone of any variety is secure. If you want to have a private conversation, never use that phone and keep it unplugged from the wall until you need it.As for management being unwary of the phone as a surveillance device, they would have to be pretty daft to not know about it.

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 10:39:18 am
content: .

author: LabSpokane
author_rank: Super Contributor
timestamp: May 06, 2015, 10:51:57 am
content: Quote from: Erica on May 06, 2015, 10:39:18 amIt's *possible* but I'm not sure how good the audio would be. My first suspicion would always start with a microphone. It's just tough to know how this handset operates without physical access to it. I would start by talking to who manages the telephone systems and see if you can get a copy of the manual. If the phone person is friendly or sympathetic, they may even tell you how the capability works. That will be quicker than reverse-engineering the telephone.

author: Fungus
author_rank: Super Contributor
timestamp: May 06, 2015, 11:02:20 am
content: Quote from: Erica on May 06, 2015, 05:37:32 amWhy?a) What would a signal on the line prove? It doesn't prove somebody is listening or not, just that there's a signal there.b) If theyarelistening and you disable the phone, they'll just switch to a much harder to detect method. Plus you just let them know that you suspect they're listening - bad move!The very best thing to do if you're under surveillance is to give them no useful information.The absolute best position to be in is that you know you're being spied on but they don't know that you know. Instead of messing with the phone you can maybe set a trap to find out if they're listening or not. Do something so you can know if somebody went somewhere or opened something based on something you said recently.

author: tggzzz
author_rank: Super Contributor
timestamp: May 06, 2015, 12:12:02 pm
content: Quote from: LabSpokane on May 06, 2015, 10:28:42 amThat's only one of the possible jokes here!Others include an anateur being able to take their own scope into a secure facility. And then use it.Or considering that if you "blow" a legitimate security service operation, they won't be best pleased.

author: David_AVD
author_rank: Super Contributor
timestamp: May 06, 2015, 12:29:25 pm
content: The phone in the photos appears to be a simple 2-wire unit, not the type (typically 4-wire) ones that have the ability to control the audio paths.It has a bog standard hook switch and what appears to be a ringer chip, DTMF chip and a handful of support parts.I seriously doubt that phone is the source of any leaked conversations.

author: Fungus
author_rank: Super Contributor
timestamp: May 06, 2015, 12:30:41 pm
content: Quote from: David_AVD on May 06, 2015, 12:29:25 pmNot unless it's been tampered with.

author: David_AVD
author_rank: Super Contributor
timestamp: May 06, 2015, 12:34:18 pm
content: Quote from: Fungus on May 06, 2015, 12:30:41 pmI assumed the pictures posted were of the phone in question? Maybe that's not the case?

author: Fungus
author_rank: Super Contributor
timestamp: May 06, 2015, 12:38:48 pm
content: Quote from: David_AVD on May 06, 2015, 12:34:18 pmI haven't seen the pictures but maybe the DTMF chip is a fake or something. This isn't the 1980s where you'd be able to see a bunch of wires and batteries in a tampered-with phone.I'm thinking erica got the wrong oscilloscope. The MSO1104Z would have been better. The built-in logic analyzer would have been able to look at that chip. It's a bit more expensive but worth it for the peace of mind.

author: SL4P
author_rank: Super Contributor
timestamp: May 06, 2015, 12:44:30 pm
content: All indications are that this us a troll, but a fun one to engage!All the OP posts suggest an employee in a modest role, with little or no access to anything more secure than their work locker.His employers are not interested in scanning his workplace unless he's making these posts during office hours.The phone is an analogue phone for use on a POTS style circuit - very unusual in any structured organisation that I've dealt with in the last ten years.Taking a scope or anything else to work suggests they don't have their own, or OP has no access to them. Take from that what you may.If they're in a clerical role (documentation, accounts etc) then they seriously should look for a job with less 'intrigue'!2c worth.

author: xrunner
author_rank: Super Contributor
timestamp: May 06, 2015, 01:20:27 pm
content: Quote from: Erica on May 05, 2015, 10:38:14 amJust pick up the phone and say this -"Hey Frankie I'm dropping off the bag of money at 3 PM today over at the _______ store on (pick a nearby location). You can pick it up there!"Then go there and see who shows up.

author: Towger
author_rank: Super Contributor
timestamp: May 06, 2015, 01:36:07 pm
content: Quote from: smjcuk on May 06, 2015, 10:01:47 amThere solution to the tapping went as follows:Normal phone call: Used a normal phone line.Normal phone call were you wanted to feed the MoD information or did not care if over heard: Used scrambling system over normal phone line.Top Secret phone call: They installed a phone line in a farm several miles a way from the site and ran their own copper through the fields. Calls were made in the clear, as a scrambled call would be picked up in the exchange and investigated. He was a strong believe there is no such thing a secure scrambling system.

author: LaserSteve
author_rank: Super Contributor
timestamp: May 06, 2015, 01:39:11 pm
content: Monitoring of Employees is very, very, very, real in large corporations.Two employers ago, The lady in the cubical next to me spent way too many hours with a headset on when her principal job was training. So one day she left the desk with a certain screen up. We took a look. Very interesting software running.This was of course, at a corporation where people were afraid to make friends in the cafeteria, and this Dutch multinational had one hundred years of experience in manipulating staff.What they were doing is very much LEGAL in the USA.However these days the "bug" is a tap at the PBX switch or IN the multiplex card, not at the desk, unless a co-worker has done something very crude and unauthorized.On a 2 wire POTS phone, in the US, its a simple matter of paralleling two wires down stream to another device. Electronically Virtually invisible to a novice, unless you do TSM for living.Where I work now, some technicians with private offices have wired a DPDT on the ISDN lines to disconnect the phone when talking in their office.Steve

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 06, 2015, 01:50:14 pm
content: Yes. Microsoft even promote it with Lync for example. Total bastards.Quote from: Towger on May 06, 2015, 01:36:07 pmThat's about right.I have some even worse stories but I'm not allowed to tell anyone until 2048...

author: LaserSteve
author_rank: Super Contributor
timestamp: May 06, 2015, 02:15:31 pm
content: But did they pay the Farmer well?Steve

author: xrunner
author_rank: Super Contributor
timestamp: May 06, 2015, 02:20:31 pm
content: Quote from: smjcuk on May 06, 2015, 01:50:14 pmYou can do it over the phone.

author: LabSpokane
author_rank: Super Contributor
timestamp: May 06, 2015, 04:05:26 pm
content: Erica,How did you verify that the ringer functions as a microphone? Did you use the scope?

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 04:37:27 pm
content: .

author: paulie
author_rank: Frequent Contributor
timestamp: May 06, 2015, 04:46:00 pm
content: I can verify from personal experience the piezo ringer from a phone does make an excellent mic. Only when removed from the circuit. As mentioned previously they are not connected to the phone line at all but instead driven by a special purpose IC. No chance for eavesdropping. Anybody who claims otherwise is blowing smoke.ps. What ARE those yellow avatar squares?

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 04:49:42 pm
content: .

author: paulie
author_rank: Frequent Contributor
timestamp: May 06, 2015, 04:54:54 pm
content: Yes, that's what I said. Nothing would get past the ringer circuit into the line.ps. Erica has NO yellow squares, Does that mean he is a 3rd class citizen?

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 05:04:00 pm
content: .

author: TerraHertz
author_rank: Super Contributor
timestamp: May 06, 2015, 05:18:40 pm
content: Ok.... I'm afk for a while, and what conversation there was has been deleted. Erica, why did you edit your original posts to wipe them? I gather you posted photos of the phone and circuit. I missed them. Can't help you if you're going to do stuff like that.

author: LabSpokane
author_rank: Super Contributor
timestamp: May 06, 2015, 05:20:51 pm
content: Quote from: Erica on May 06, 2015, 04:37:27 pmOK. So the tone gen is external to the ringer. As for whether audio makes it upstream, who knows.If these truly are two wire POTS phones - if you can connect two telephones in parallel with one handset in the hook, it may be possible to show/disprove tapping using the ringer as a speaker. You may be able to simulate what is going on at the PBX by using the other phone as a listener. If 4 wire digital, it's not so simple.If you have a smartphone, downloading a "tone" app such as Dog Whistler can provide you with a convenient reference tone. I typically used 1kHz as a sample tone for audio work.

author: paulie
author_rank: Frequent Contributor
timestamp: May 06, 2015, 05:22:19 pm
content: Quote from: Erica on May 06, 2015, 05:04:00 pmooops.. sorry. According to a Yahoo forum 2/3 of the "ladies" on forums like this are actually trolls or guys who wish they were ladies. Not filling in at least general country info in the avatar does make posters suspect so I just assumed....Any way, signals go from in to out for op amp and transistor circuits but usually not the other way around.ps. Is it possible what they say about TH having obsessions over deleted posts is true?

author: PeterFW
author_rank: Frequent Contributor
timestamp: May 06, 2015, 05:22:46 pm
content: This thread feels like a prank...And when you try to read the thread every post on the first few pages from the threadstarter has been deleted allready by the threadstarter, or should i say redacted?Are you that paranoid that "They" will read about your problem on a forum?If they tapped your phone they monitor your internet annyway.My advice:http://www.howardforums.com/attachment.php?attachmentid=84281

author: LabSpokane
author_rank: Super Contributor
timestamp: May 06, 2015, 05:24:11 pm
content: And I just read your last post Erica. If the phone has no voltages at all when on the hook, that's a bit mysterious. You should be reading -48V or so on the line side of the hook switch at least.

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 05:43:55 pm
content: Quote from: LabSpokane on May 06, 2015, 05:24:11 pmThe measurements I was referring to were taken when the phone was disconnected.

author: LabSpokane
author_rank: Super Contributor
timestamp: May 06, 2015, 05:53:30 pm
content: Quote from: Erica on May 06, 2015, 05:43:55 pmThe phone is line-powered so you should not see anything when disconnected.

author: paulie
author_rank: Frequent Contributor
timestamp: May 06, 2015, 06:06:18 pm
content: Erica mentioned audio signals generated by the ringer transducer. I agreed but noted they don't reach the line. Looks like she did trace them into the ringer circuit a ways but no further so we were in agreemant. Audio not related to line voltages.BTW thanks again for the work with those reference. It didn't solve my immediate problem getting simple readings but very informative in other areas. I did get help from another source and will post all those results when the zener types are done "baking". Another week or two I think.

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 06, 2015, 06:11:19 pm
content: Quote from: Erica on May 06, 2015, 05:04:00 pmBecause in modern telephones (such as the one you show in your photos), the "ringtone" is locally generated inside the telephone. There is no direct or indirect connection between the piezo buzzer and the phone line. Furthermore, modern phones tend to be digital and never have ANY kind of analog audio signal on the line at all.QuoteSorry, that doesn't make any sense. The telephone set is powered from the line. So you should not see any voltages anywhere unless the phone is plugged into the phone line. Disconnecting the piezo buzzer "ringer" should make no significant difference to any voltages inside the phone.Back two generations ago, phone ringers were big coils, AC coupled directly across the phone line. However the moving part was just a brass ball on the end of a spring-wire and it is hard to imagine how that could pick up sound waves any better than a rock.

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 06:17:55 pm
content: .

author: kjs
author_rank: Regular Contributor
timestamp: May 06, 2015, 06:20:41 pm
content: These were the stone age bush drum style phones. What you have in the one you had in the picture is completely different.

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 06:29:06 pm
content: .

author: PA0PBZ
author_rank: Super Contributor
timestamp: May 06, 2015, 06:33:49 pm
content: Quote from: Erica on May 06, 2015, 06:29:06 pmNo, that's what the others are trying to tell you all day. There is NO AC path from the buzzer back to the line in the modern phones. There is a little IC that detects the ringing current on the line and then sends a signal to the buzzer. There is NO possible way from the buzzer back into the IC and then to the line.Please understand that these old ringers where directly coupled to the line, modern ones are not!

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 06:40:13 pm
content: .

author: LabSpokane
author_rank: Super Contributor
timestamp: May 06, 2015, 06:45:06 pm
content: At what frequency?

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 06:52:48 pm
content: .

author: paulie
author_rank: Frequent Contributor
timestamp: May 06, 2015, 07:04:46 pm
content: Quote from: Erica on May 06, 2015, 06:40:13 pmFREE ENERGY !!!I knew it would come true some day if we just kept the faith. And probably 50hz or 60hz which will be very convenient for powering household appliances.

author: Erica
author_rank: Regular Contributor
timestamp: May 06, 2015, 07:09:28 pm
content: .

author: David_AVD
author_rank: Super Contributor
timestamp: May 06, 2015, 08:47:27 pm
content: Much more likely you're measuring stray mains induction due to the way you're doing the measurement.

author: SL4P
author_rank: Super Contributor
timestamp: May 06, 2015, 09:57:54 pm
content: The photos have been pulled by the OP, however, virtually all analog handsets use a transformer to bridge the line pair. (This IS an older analog handset)The critical point I'm making is that transformers only pass AC (Approved Conversations). not DC (Discreet Conversations), so you're safe until they install a digital phone system / handsets of some sort.

author: David_AVD
author_rank: Super Contributor
timestamp: May 06, 2015, 10:47:41 pm
content: Quote from: SL4P on May 06, 2015, 09:57:54 pmYou just made my morning.

author: Erica
author_rank: Regular Contributor
timestamp: May 07, 2015, 06:44:11 am
content: .

author: Erica
author_rank: Regular Contributor
timestamp: May 07, 2015, 07:24:13 am
content: .

author: Erica
author_rank: Regular Contributor
timestamp: May 07, 2015, 07:27:29 am
content: Quote from: David_AVD on May 06, 2015, 08:47:27 pmI made a mistake there is some voltage even with the ringer absent. I don't know where its coming from. Its very noisy not stable or periodic.

author: Fungus
author_rank: Super Contributor
timestamp: May 07, 2015, 07:36:48 am
content: Quote from: Erica on May 07, 2015, 07:24:13 amYes, definitely.

author: Erica
author_rank: Regular Contributor
timestamp: May 07, 2015, 07:43:01 am
content: .

author: David_AVD
author_rank: Super Contributor
timestamp: May 07, 2015, 07:49:08 am
content: Quote from: Erica on May 07, 2015, 07:43:01 amIn one of the capacitors possibly.

author: Erica
author_rank: Regular Contributor
timestamp: May 07, 2015, 08:02:15 am
content: .

author: tggzzz
author_rank: Super Contributor
timestamp: May 07, 2015, 08:06:54 am
content: Quote from: Erica on May 07, 2015, 08:02:15 amNo better and no worse than the concept of someone dismantling equipment and doing unofficial investigations in a "a high security government facility". As you described in msg37https://www.eevblog.com/forum/projects/telephone-eavesdropping/msg667512/#msg667512

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 07, 2015, 08:14:24 am
content: Quote from: David_AVD on May 07, 2015, 07:49:08 amBlame it on the capacitors eh? Always the capacitors. At least consider the resistors. That V-I curve is suspiciously straight if you ask me.

author: SL4P
author_rank: Super Contributor
timestamp: May 07, 2015, 08:32:07 am
content: The 150mv could be ambient room noise being picked up by the piezo transducer...and lifting the circuits floating potential

author: Erica
author_rank: Regular Contributor
timestamp: May 07, 2015, 08:37:15 am
content: .

author: David_AVD
author_rank: Super Contributor
timestamp: May 07, 2015, 08:44:26 am
content: Quote from: Erica on May 07, 2015, 08:02:15 amIt was the joke of least resistance.

author: LabSpokane
author_rank: Super Contributor
timestamp: May 07, 2015, 02:38:14 pm
content: Erica,Can I ask why talking to the folks that maintain the telephone system is not a possibility? If such a feature is available, it is almost certainly in the administrative manual.

author: Erica
author_rank: Regular Contributor
timestamp: May 07, 2015, 02:44:08 pm
content: .

author: Erica
author_rank: Regular Contributor
timestamp: May 07, 2015, 02:47:45 pm
content: .

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 07, 2015, 02:57:02 pm
content: Perhaps there isn't anything there.

author: Erica
author_rank: Regular Contributor
timestamp: May 07, 2015, 02:58:58 pm
content: .

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 07, 2015, 03:16:35 pm
content: That's approaching irrationality. I'd quit and find something else to do.

author: LabSpokane
author_rank: Super Contributor
timestamp: May 07, 2015, 03:26:35 pm
content: Quote from: Erica on May 07, 2015, 02:44:08 pmOK. At this point you have a problem that an electrical engineer cannot solve. Good luck.

author: PeterFW
author_rank: Frequent Contributor
timestamp: May 07, 2015, 03:58:35 pm
content: Quote from: Erica on May 07, 2015, 02:58:58 pmMaybe you should go for for a psyche evaluation, seriously.(Yes i know, delusional people will not do that out of their own free will.)

author: Erica
author_rank: Regular Contributor
timestamp: May 07, 2015, 04:04:36 pm
content: .

author: Monkeh
author_rank: Super Contributor
timestamp: May 07, 2015, 04:13:53 pm
content: It is totally irrelevant.No matter what we say or do, you will be convinced someone is bugging the phones through the ringer. Get help.

author: lincoln
author_rank: Regular Contributor
timestamp: May 07, 2015, 04:19:14 pm
content: Quote from: Erica on May 07, 2015, 02:44:08 pmyour awfully trusting of this bunch, how do you know your internet device is not compromised? you need to be careful. The sort of people that bug phones can to other things...Quote from: smjcuk on May 07, 2015, 02:57:02 pmThat's what they want you to think.

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 07, 2015, 04:22:29 pm
content: Quote from: Erica on May 07, 2015, 04:04:36 pmYes, that is correct. When used as a simple AC device (a buzzer) there is no difference between "positive" and "negative" as the signal alternates between positive and negative hundreds or thousands of times per second. (Which is why they call it "Alternating Current")

author: paulie
author_rank: Frequent Contributor
timestamp: May 07, 2015, 04:24:41 pm
content: Quote from: Erica on May 07, 2015, 02:47:45 pmProbably not wasted since you have learned a lot about electronic equipment and how to use it. This is a very useful talent for work and play. Also look at all the friends you've made here and the fun we've had. That assumes yours is a valid request for help and not just trolling or lonely.Posters are taken more seriously and get more help when at least putting country in the avatar. Those who don't always a bit suspect. Maybe helps determine whether problems are cultural, psychological, or technical. Note that drones need more than that general information to target your house.

author: Erica
author_rank: Regular Contributor
timestamp: May 07, 2015, 04:29:10 pm
content: .

author: SArepairman
author_rank: Frequent Contributor
timestamp: May 07, 2015, 04:35:05 pm
content: Well if you take the peizobuzzer and do both direction impedance tests on it, and there is something of interest seen, and all the phones you think have been tapped are modified (and the other ones are not by a wide margin, I.E. not factory error, try to see if there is a serial # pattern or such on them).given the fact that it seems that you work at a high value target then maybe it is a sign of malice.Can you swap one of the tapped phones by desoldering the piezobuzzzer and doing a crude ass repair on it( im talking bubble gum and popsickle sticks here, make it work, but do some UGLY soldering with non eutectic crappy high temp solder and a too cool iron, so it freezes over and stuff.. but you also wanna make sure at least a portion of the solder joint works well and wont break but LOOKS LIKE SHIT. Perhaps put some epoxy down on it that you photograph after hardening to show tampering. so it looks like a office guy did it that knows a bit about repair, you know, so it looks like he just got fed up n did it with a ciggarette lighter and some roofing lead. Swap the polarity on it, and leave it alone to see if they fix it nicely.perhaps carefully include some false evidence inside of the telephone so it looks like the person who uses it modified it, so they think its just a diy techie type, not some survilence pro. like a piece of lint or something. some inappropriate tape (scotch tape) would be good too.you should be able to see signs of rework if someone did swap out the piezo buzzers recently, have a look at it under the microscope.

author: Andy Watson
author_rank: Super Contributor
timestamp: May 07, 2015, 04:37:21 pm
content: Quote from: Erica on May 07, 2015, 04:29:10 pmHe does not say "only". His mic will work with either wire. He uses the black to ground because the black piezo wire is connect to the brass metal which affords some electrical shielding.

author: SArepairman
author_rank: Frequent Contributor
timestamp: May 07, 2015, 04:39:02 pm
content: Quote from: Andy Watson on May 07, 2015, 04:37:21 pmcould it be the lack of shielding allows some parasitic HF modulated signal to couple through on the PBX and allow itself to be decoded with a special RF receiver?I mean, at a state level, they will bombard a location with ionospheric bounced Microwave or local transmitter in such a way as to exploit precisely these odd things.I.E. the phone has a fair bit of EMI in it (design flaw), if the piezo picks it up, it transfers all the way through the system and down the wire. takes some alt path that bypasses filters.Like, i think i read about PC data being accessed as super imposed data on a HF carrier or something weird like that? they don't build computers and stuff to hold in information when they are being bombarded with odd GHz band energies.http://en.wikipedia.org/wiki/Tempest_%28codename%29i mean , im pretty sure they can end up stealing computer data via the PBX just from radiated emissions, if they really wanted to.

author: Erica
author_rank: Regular Contributor
timestamp: May 07, 2015, 05:21:40 pm
content: .

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 07, 2015, 06:13:30 pm
content: Quote from: Erica on May 07, 2015, 04:29:10 pm1) The guy is hardly an electrical engineering expert. He is a self-proclaimed hacker.2) It would work EITHER way he connected it. He just has a limited imagination.3) Notice VERY CAREFULLY that he says "but it does NOT pick up acoustic sounds". (listen at 2:44)So, unless you are holding the ringer buzzer to your throat, how do you think they are using that to spy on anybody?"It does NOT pick up acoustic sounds." I repeated that in case you missed it.

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 07, 2015, 06:17:40 pm
content: Quote from: Erica on May 07, 2015, 05:21:40 pmIt doesn't mean anything. Because you don't have a diaphragm, and you don't have a coil, either.

author: Erica
author_rank: Regular Contributor
timestamp: May 07, 2015, 06:20:10 pm
content: .

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 07, 2015, 06:27:02 pm
content: Quote from: Erica on May 07, 2015, 06:20:10 pmNo, and no.QuoteYes, you created a piezoelectric microphone by (presumably) connecting the gadget directly to a sensitive audio amplifier.Congratulations. You have re-invented something you grandfather new about.We are assuming that is how you conducted your experiment, absent any actual description.But, in a telephone, the piezo buzzer is NOT connected to an audio amplifier.Quite the opposite. It is connected to a crude oscillator and the OUTPUT (not the INput) of an amplifier.And there is no direct connection between the piezo element and the telephone line, analog or digital.

author: LabSpokane
author_rank: Super Contributor
timestamp: May 07, 2015, 06:51:29 pm
content: Erica,I just have to ask. You say you cannot talk to anyone. So what do you tell them when you take their telephone and disassemble it?

author: Erica
author_rank: Regular Contributor
timestamp: May 07, 2015, 07:13:34 pm
content: .

author: SL4P
author_rank: Super Contributor
timestamp: May 07, 2015, 09:19:28 pm
content: My signature says it all.

author: Erica
author_rank: Regular Contributor
timestamp: May 09, 2015, 09:23:58 am
content: .

author: SL4P
author_rank: Super Contributor
timestamp: May 09, 2015, 09:28:20 am
content: ... and what's the relevance of that article to your 'situation'?That article is proposing the piezo as 'transmitting' element if a short range ultrasonic wireless link.So what?

author: Erica
author_rank: Regular Contributor
timestamp: May 09, 2015, 09:30:07 am
content: .

author: PeterFW
author_rank: Frequent Contributor
timestamp: May 09, 2015, 09:42:18 am
content: Quote from: Erica on May 09, 2015, 09:30:07 amPlease!Either go to your next goverment organisation and tell them or realise that you lost quite a few of your marbles and are a bit wonky in the head area.

author: Erica
author_rank: Regular Contributor
timestamp: May 09, 2015, 09:49:57 am
content: .

author: SL4P
author_rank: Super Contributor
timestamp: May 09, 2015, 09:54:25 am
content: Eric, Erica -if you look back at this thread, I think you'll see a lot of people genuinely tried to help a novice understand and identify your concerns, but you refused to listen or learn.Perhaps you should give up the electronics, and go for American Idol or similar, as you're likely a better actress than engineer.A clerical job is stretching it a bit too far.

author: Erica
author_rank: Regular Contributor
timestamp: May 09, 2015, 10:07:07 am
content: .

author: tggzzz
author_rank: Super Contributor
timestamp: May 09, 2015, 10:46:17 am
content: For amusement only, people might like to look at this thread - in particular the OP's name, the phrasing of the original post, and the reason given for wanting the answer.http://www.edaboard.com/thread337071.html#post1438122

author: Erica
author_rank: Regular Contributor
timestamp: May 09, 2015, 10:49:14 am
content: .

author: PeterFW
author_rank: Frequent Contributor
timestamp: May 09, 2015, 11:09:07 am
content: So... i was right. Just a very elaborate troll and not a crazy person with mental problems.Well... ok, he has got mental problems but still...

author: tggzzz
author_rank: Super Contributor
timestamp: May 09, 2015, 11:20:55 am
content: Quote from: Erica on May 09, 2015, 10:49:14 amPlease explain why reading the new posts onanotherelectronics board constitutes stalking.On second thoughts, don't bother.

author: tggzzz
author_rank: Super Contributor
timestamp: May 09, 2015, 11:22:10 am
content: Quote from: PeterFW on May 09, 2015, 11:09:07 amI don't think we have sufficient evidence to distinguish between either unattractive possibility in yourfirstsentence...

author: SL4P
author_rank: Super Contributor
timestamp: May 09, 2015, 11:57:50 am
content: I also don't agree that it was anelaboratetroll... rather. an unsophisticated newbie, acting like he knew some technical terms and thought he had us 'working on' his problem after the first half dozen posts.

author: paulie
author_rank: Frequent Contributor
timestamp: May 09, 2015, 03:42:32 pm
content: Quote from: Erica on May 09, 2015, 10:07:07 amYay!Troll accusations aside you need a thick skin to persist on internet forums. Besides naysayers, goody two shoes, and plain turds there are some willing to help or at least learning from those. A few just enjoy watching noobs spin.It's also quite common to see beginners ignore good advice and follow wild goose chase from those they are romantically attached. The ones most liked are not always the ones with the useful information. I personally get a huge kick taking advantage of this situation. Better than TV (at least during rerun season).

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 09, 2015, 04:47:52 pm
content: As you get older, time speeds up, your days drift into oblivion before you know it and every second crawls away from your desperate grasp. To live a shallow life at any time is to live a life of regret and only ignorance hides you from that until its too late to do anything about it.

author: paulie
author_rank: Frequent Contributor
timestamp: May 09, 2015, 05:22:38 pm
content: Wow man... Deep man. How do you do that? Cutting right through the facade man, and looking straight into my soul. Is it possible my life is doomed to a fate of lonely despair? Missed opportunities and waste? Foolish arrogance?Naaaaahhhh.....

author: TerraHertz
author_rank: Super Contributor
timestamp: May 09, 2015, 05:29:54 pm
content: Quote from: paulie on May 06, 2015, 05:22:19 pmIn general it's a dislike of censorship, whatever the excuse. *Especially* when the motivation is political, but a pretense is made that it's not about politics.However in this thread's case, it's different. OP's first post came across as either a nutter, or someone with a legitimate problem but way out of their depth technically. I like to give people the benefit of the doubt, and at least see how the conversation goes. Besides, it can be interesting whatever the case.But deleting one's own thread-starter post and most subsequent ones (inconsistently!) is poisonous. No further interest from me.

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 09, 2015, 05:46:03 pm
content: Quote from: paulie on May 09, 2015, 05:22:38 pmMy comment was directed at el trollo, not your good self.

author: paulie
author_rank: Frequent Contributor
timestamp: May 09, 2015, 05:51:54 pm
content: I figured but thought it was worth a little fun anyway. Personally I don't think Erica was trolling. Maybe a touch of paranoia or honest technical confusion but in any case a call for help. Either way quite a bit forthcoming and hopefully appreciated.ps. TH, maybe not politics or censorship either but good 'ol internet personality conflict. Usually just good entertainment but can get tricky when one is in a position of power. The fact you're still posting here shows some credit is due.

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 09, 2015, 06:17:04 pm
content: I was thinking nutbag.I worked for a big defence company for a bit doing nefarious things followed by the software security sector (grey hat) and now backstabby financial services security and architecture, rather like dystopian fiction and consider myself to be above average on the paranoid ranking. However I try to remain within the realms of reality and science and consider the premise and outcome of this individual to be whip wooop walla walla woo batshit.

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 09, 2015, 06:33:17 pm
content: Just because you are paranoid doesn't mean that people really aren't spying on you.OTOH, spending big money on sophisticated gear when you don't understand any of the principles, and thinking that it is somehow possible to use the piezo ringer in a modern digital phone as a microphone are just too far-fetched for even the tinfoil-hat crowd.