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Wi-Fi Direct
Do you know if Wi-Fi Direct is bases on 2.4GHz or 5GHz as usual wireless
network? I can't detect the Wi-Fi Direct of my Samsung TV with Wifi Analyzer (https://play.google.com/store/apps/d...nalyzer&hl=en), any idea? should I detect it? Max |
#2
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Wi-Fi Direct
On 4/26/2017 3:51 PM, Maelmoro wrote:
Do you know if Wi-Fi Direct is bases on 2.4GHz or 5GHz as usual wireless network? I can't detect the Wi-Fi Direct of my Samsung TV with Wifi Analyzer (https://play.google.com/store/apps/d...nalyzer&hl=en), any idea? should I detect it? Max The specification at https://www.wi-fi.org/discover-wi-fi/wi-fi-direct says: "Does the specification underlying the Wi-Fi Direct certification program work on both frequency bands? Yes, the specification underlying the Wi-Fi Direct certification program supports operation in both 2.4 GHz and 5 GHz. Devices operating in the 2.4 GHz frequency band only and devices operating in both the 2.4 GHz and 5 GHz frequency bands can be certified under the Wi-Fi Direct program. Not all Wi-Fi Direct-certified devices support both frequency bands, however, so you should check which bands your devices support. " I take this to mean that it _can_ operate on both bands but not that every device will operate on both. BTW: there are so many security flaws concerning Samsung's OS in general and Wi-Fi Direct specifically that I'd hesitate to do anything with it until the 40+ known security faults are patched. |
#3
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Wi-Fi Direct
BTW: there are so many security flaws concerning Samsung's OS in general
and Wi-Fi Direct specifically that I'd hesitate to do anything with it until the 40+ known security faults are patched. I'm not worried about security problems but magnetic field in my house, I have 2 little children.. Since I usually disable my router WiFi (as a strong precaution, I know it's not established it's harmful..) I'd like to do the same with Direct WiFi of my TV Samsung UE50J6200AKX. How to? It seems you can't.. And what I asked as first was: why can't I detect the Direct WiFi with my WiFi Analyzer as any other WiFi? Maybe because when it's not used there's not field.. ? |
#4
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Wi-Fi Direct
On 4/27/2017 1:47 PM, Maelmoro wrote:
snip... And what I asked as first was: why can't I detect the Direct WiFi with my WiFi Analyzer as any other WiFi? Maybe because when it's not used there's not field.. ? From the little I understand about Direct Wi-Fi, if it is not talking to an established device it does nothing and nothing is being transmitted. There is some sort of process built in that allows the pairing and it seems likely that you would need to go through that pairing process to get it to 'talk'. There was some mention of the pairing needing to be accomplished in 30 seconds or something like that so you would have to do your detecting during that time window. |
#5
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Wi-Fi Direct
Maelmoro wrote:
BTW: there are so many security flaws concerning Samsung's OS in general and Wi-Fi Direct specifically that I'd hesitate to do anything with it until the 40+ known security faults are patched. I'm not worried about security problems but magnetic field in my house, I have 2 little children.. Since I usually disable my router WiFi (as a strong precaution, I know it's not established it's harmful..) I'd like to do the same with Direct WiFi of my TV Samsung UE50J6200AKX. How to? It seems you can't.. And what I asked as first was: why can't I detect the Direct WiFi with my WiFi Analyzer as any other WiFi? Maybe because when it's not used there's not field.. ? A Youtube video suggests there is a "Networking" menu in the TV on-screen (OSD) menu. In there, you can select "Wi-Fi" or "Wired" connection. If you flip it to Wi-fi, then you could use your RF sniffer to detect activity. The sniffer in the Youtube video, showed a Samsung set probing the airwavea about every three or four seconds or so. If you flip the connection to "Wired", the Wifi activity is supposed to stop. The Samsung site does not have a manual for your exact TV. The PDF download is "generic" and "useless'. The TV has an onscreen manual, which may or may not explain this stuff. Like, would the networking panel have a separate tick box for Wi-Fi Direct ? Dunno. Since the documentation system is not set up, to allow us to help you. ******* Disassembling a Samsung TV looks pretty simple. This one doesn't appear to have a Wi-fi module. A Wifi module should have a rectangular metal can over top of it, just like the tuner module on the input board has both a shield, and a F-series coax connector. http://www.techrepublic.com/pictures...v-un55d6300sf/ Viewed from the back, that TV has three PCBs. The one on the left is the Input/VideoProcessor board. It accepts a number of HDMI signals, the board has a TV tuner module with coaxial connector. It has a processing chip with external memory (that does video enhancement, adjusts the LED light level for better dynamic contrast). On that TV, the board on the left (viewed from the back), is the only "Smart" board. Some TVs, the Smart part is a separate Android kind of processor board. That's because the dedicated video processor chip, isn't usually intended to "do everything". But times change, the level of integration is constantly increasing, so anything is possible. The middle PCB in that picture, is the LCD panel driver. It converts the low-amplitude, differential, parallel bus ribbon cable from the left board, into a higher voltage scan pattern to drive the LCD. The right-most board is the power converter. On one Samsung TV, the input board appears to have an actual black "bump" for a Wifi module. The Wifi module should be inside its own tin can, so it doesn't "spray" any adjacent chips with RF and cause them to malfunction. That's called EMI containment. And vice-versa. the tin can prevents processor digital emissions, from upsetting the Wifi amps and stuff. The main message of the above web-link, is the unit appears to be easy to take apart. However, there are various random wires from switches of various sorts on the chassis, and you have to be careful with those. The demo unit on the web page, doesn't appear to use any glues, or wire assemblies designed to destruct as soon as you open the unit. A good design, would have a sticker over one of the back panel screws, marked "Warranty Void if removed". So that's the only logistical barrier to examination, is the potential for a Warranty sticker to be placed on one of the screws. That scheme is used on ATX power supplies, to keep people out :-) If you purposely switch on the Wifi, you may be able to localize where the Wifi signal is located. And then come up with a solution. If it was my TV set, and I felt that strongly about it, I would find the Wifi module inside the unit, and "take action". For regular Wifi antennas, I would replace the antenna cable with a 50 ohm terminator SMA. (There could be two antennas.) That prevents emission of Wifi signals, and keeps the electronics happy (SWR = approx 1.0). If the unit uses patch antennas, it's a Module-On-Board design, then it may be too difficult to find a nice neat-and-clean mod to disable it. Using your sniffer, and "turning up" the Wifi temporarily (i.e. use ordinary Wifi protocol, not Wifi Direct), may at least allow finding the side of the TV with the module. (The TV could probe the room every three or four seconds.) Shielding can be difficult. Building a Faraday cage, you cannot make a complete cage. Using absorptive mats, the signal would be attenuated (perhaps below health-effects level), but the signal might not be completely eliminated. Paul |
#6
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Wi-Fi Direct
On 27/04/2017 19:58, John McGaw wrote:
On 4/27/2017 1:47 PM, Maelmoro wrote: snip... And what I asked as first was: why can't I detect the Direct WiFi with my WiFi Analyzer as any other WiFi? Maybe because when it's not used there's not field.. ? From the little I understand about Direct Wi-Fi, if it is not talking to an established device it does nothing and nothing is being transmitted. There is some sort of process built in that allows the pairing and it seems likely that you would need to go through that pairing process to get it to 'talk'. There was some mention of the pairing needing to be accomplished in 30 seconds or something like that so you would have to do your detecting during that time window. Samsung support told me that I haven't to be worried because when the TV is off even if my mobile phone detect the TV this isn't "WiFi" but a weak Bluetooth. And only when you establish a connection the Direct WiFi works, so only at this time there's a WiFi field around. Do you think it's right? |
#7
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Wi-Fi Direct
Maelmoro wrote:
On 27/04/2017 19:58, John McGaw wrote: On 4/27/2017 1:47 PM, Maelmoro wrote: snip... And what I asked as first was: why can't I detect the Direct WiFi with my WiFi Analyzer as any other WiFi? Maybe because when it's not used there's not field.. ? From the little I understand about Direct Wi-Fi, if it is not talking to an established device it does nothing and nothing is being transmitted. There is some sort of process built in that allows the pairing and it seems likely that you would need to go through that pairing process to get it to 'talk'. There was some mention of the pairing needing to be accomplished in 30 seconds or something like that so you would have to do your detecting during that time window. Samsung support told me that I haven't to be worried because when the TV is off even if my mobile phone detect the TV this isn't "WiFi" but a weak Bluetooth. And only when you establish a connection the Direct WiFi works, so only at this time there's a WiFi field around. Do you think it's right? https://en.wikipedia.org/wiki/Wi-Fi_Direct "Wi-Fi Direct negotiates the link with a Wi-Fi Protected Setup system that assigns each device a limited wireless access point. The "pairing" of Wi-Fi Direct devices _can_ be set up to requi * proximity of NFC (near field communication) * a Bluetooth signal * button press on one or all the devices. " Other articles I could find, don't even mention that. One of the Bluetooth standards even introduced data carriage over Wifi, as part of Bluetooth. The Bluetooth in that case, set up the basic connection, and once the connection was in place, a parallel connection using Wifi could be used to enhance the data rate. And this was considered to be a Bluetooth connection, even though the Wifi hardware was being used for carriage. ******* Then the article here says: http://www.samsung.com/au/support/skp/faq/1048477 "Tap Wi-Fi Direct. The device will scan for Wi-Fi Direct devices automatically " That appears to be done from an Android SmartPhone, but it implies the TV set is "listening" on the Wi-fi interface. ******* https://www.wi-fi.org/discover-wi-fi/wi-fi-direct "Wi-Fi Direct devices emit a signal to other devices in the area, letting them know a connection can be made. Users can view available devices and request a connection, or may receive an invitation to connect to another device. When two or more Wi-Fi Direct-certified devices connect directly, they form a Wi-Fi Direct Group using Wi-Fi Protected Setup (WPS) and the latest Wi-Fi security [WPA2???] " So that agrees with the scenario in the Samsung article. The first sentence suggests an SSID mechanism, but it could just as easily be done by the subtending device only running its receiver, and "answering" when probed. Then another paragraph says: "Mobile phones, cameras, printers, PCs, and gaming devices connect to each other directly... Connecting Wi-Fi Direct-certified devices is easy and simple, with: the push of a button tapping two NFC-capable devices together or entering a PIN. Moreover, all Wi-Fi Direct connections are protected by WPA2 " ******* Are you feeling safe yet ? :-\ The description is wishy-washy enough, to have been written by the Bluetooth group. Each of these manufacturers should be providing documentation of their own, and not blowing this stuff off. It should state in the downloadable PDF manual, how each and every device works. ******* This is more technical - see page 2 "Group Formation" http://www.it.uc3m.es/pablo/papers/p...wifidirect.pdf Paul |
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