Difference between wi-fi router and usb modem devices - connection

Both usb and wifi routers are modes of connectivity.
Is there any difference between the two devices? Is it correct to say both are same?

While the term USB modem refers to any type of data/fax/voice modem device which can be connected to a computer using USB, the term more commonly describes a specific portable USB device that looks similar to a USB flash drive and can be as small as 100 x 35 x 23mm in physical size and weigh only around 25grams . These small portable USB fax modems do not require a power source and can be plugged into any USB port on your PC, notebook, or Macintosh computer and can also be disconnected from the computer without turning off the system. One end of the portable USB modem will have a USB interface, while the other end will have an RJ-11 port for connecting your phone line.
A wireless router is a device that performs the functions of a router and also includes the functions of a wireless access point. It is used to provide access to the Internet or a private computer network. It can function in a wired LAN (local area network), in a wireless-only LAN (WLAN), or in a mixed wired/wireless network, depending on the manufacturer and model.

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Connet to Raspberry PI on Extender

So here's my setup. Our home wifi is Verizon, with a router in the living room connected to the incoming coax, with a wireless extender upstairs in my office and another extender in the basement, both of which are also connected to the coax network. All of this basic configuration works fine for our basic wireless needs (phone, laptops, tablets, etc.).
The issue I'm having is that I have a Raspberry PI connected wirelessly to the upstairs wifi extender that runs a small Postgres database that I use for my programming tinkering. If I'm connected on my laptop or PC to that extender, I can use PG Admin or remote desktop to connect to the rPI using its IP address. However, if I'm connected to the main router or the other extender, I can't access the rPI anymore - even pinging the IP address times out. I'm assuming this is because the extender the rPI is connected to is technically a different wifi network than the ones broadcast by the router or the other extender. I'm hopeful that maybe there's some way to configure this setup that I can access the rPI from my in-home network no matter which device I'm connected to, because it's all linked via the coax that runs through the house, but I'm not sure how to make that happen, but I don't have the knowledge in this specific area to know where to adjust my settings.
Anyone have any ideas? I feel like it could either be a simple fix or something that's totally impossible. Any help is appreciated.
The issue was that I had configured both extenders and the router to broadcast on the 2.4ghz and 5ghz bands (different SSID on the 2.4ghz band) for older devices that didn't seem to like the 5ghz netowkr. The rPI was connected to the 2.4ghz network, but my laptop was connected to the 5ghz one. Switching the rPI to use the 5ghz band (or plugging it in to the extender, or switching the laptop to use the 2.4ghz network) made it visible.

Raspberry Pi 2 Internet Connection by micro-USB

I'm using a RPi 2 and I supply it by the USB port of my PC, I already have made the PC share internet by the ethernet cable. I was wondering if it's possible to establish an internet connection by the same cable that does the voltage supply for RPi?
I have this doubt because I work sometimes with a BeagleBone Black and I can make a internet sharing by the same USB cable that does the voltage supply. Which is a very pratical resource from this platform.
For RPI: The micro USB is only for power supply. You cannot use it share connection or login to RPI. RPIs can be shared internet only by using Ethernet crossover cable. AFAIK there is no particular reason why RPI like that.Most users share internet to RPI by connecting it to router or PC via Ethernet cable.
But for BBB: Yes, you can use the Powersupply cable to share the internet connection and even login in to BBB.

Wired connection from iPhone to Raspberry Pi

I would like to build an application on my iPhone that connects to my raspberry Pi. Because these are going to be in close proximity (next to each other), I'd like to use the wired connection (lightning port to USB) to communicate. Is this possible or must I use wireless technologies? My assumption is that wired would be better as it ensures a connection and would be faster, however, I am open to be corrected.
This is related to a hobbyist project where I want to access a raspberry pi sensor on my iphone. The sensor (and Pi) will be next to the iphone. I'm building a custom weird case to combine them.
Any thoughts much appreciated.
Thanks
Iain
For communication with peripheral devices (Raspberry Pi for example) you have several alternatives.
UART via 30-pin or lightning connector (MFi needed)
USB via 30-pin or lightning connector (MFi needed)
Quick start: Microchip's development kits. This module can prolong communication to RPi or you can try to implement the Accessory stack (and communication with authentification chip) to RPi itself.
FSK or similar modulated-audio communication via audio-jack (no MFi needed)
You would have to implement hardware FSK modem on the RPi side and a software one on the iOS side. It is a bit tricky but by no means impossible.
Of course you could implement software modem on the RPi side, too. But since RPi doesn't have audio input you would have to use an USB audio card or something. Or complicate your life trying to sample an analog pin fast enough.
User not really Jake made a quite impressive list of links on this topic here on SO.
Bluetooth as an External Accessory (MFi needed)
Quick start: RN-41/42-APL
Easy to use Bluetooth stack. Communication with authentification chip is handled by the BT module. Note that when communicating with iOS devices data troughput is not much better than when using BLE modules.
Bluetooth as a BLE module (no MFi needed)
Data troughput not much worse then the old BT. Implementing the communication might be a bit more tricky code-wise. This module seems interesting.
WiFi communication (no MFi needed)
WiFi might be a good choice. But for your device and iOS device to be able to find eachother you will need either static IP (for the server device) or minimal Zeroconf (Bonjour) implementation.
When using WiFi you can go either with infrastructure network (using external Access Point) or you could go with AdHoc (created by your device). Later seems promising but be careful - iOS7 & AdHoc network don't seem to work well together yet.
With WiFi you have many modules to choose from. A simpler to use would be a module like RN-XV WiFly Module. TCP stack is already implemented in the module - you can use simple UART communication. I'm not sure how to implement Zeroconf on this one.
Or there are raw WiFi modules like MRF24WG0MA/MB. They are stable and reliable and they can be used on home-etched PCB. Downside for RPi user would be that you would almost certainly need an PIC24 or something between the RPi and MRF24W. Microchip provides free TCP/IP stack for their microcontrollers and this stack includes Zeroconf.
And the easiest way: you could simply use a WiFi dongle (with RPi) for communication. Zeroconf should be easy enough to implement on the RPi - and it's not even needed at the begining if you are ok with assigning static IP to the RPi (if it acts as a server).
This is not possible without signing up for apples MFI program. You have to pay and sign a bunch of NDA's.
https://developer.apple.com/programs/mfi/
You can use other methods, like bluetooth and connection over the audio port.
While #RokJarc's answer is pretty complete, I've also had success with both wired (lightning to usb) and wireless connections using iOS's personal hotspot. Here are the steps:
For wired, on the Pi, install ipheth-utils:
sudo apt-get install ipheth-utils
And add an eth1 network interface by editing /etc/network/interfaces to include:
allow-hotplug eth1
iface eth1 inet manual
For wireless, make sure /etc/network/interfaces has a wireless network entry such as:
allow-hotplug wlan0
iface wlan0 inet manual
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
If you are using wpa_supplicant and add a network entry for the iPhone's hotspot in /etc/wpa_supplicant/wpa_supplicant.conf:
network={
ssid="Banana Phone"
psk="ring ring ring"
key_mgmt=WPA-PSK
id_str="banana"
priority=3
}
The ssid should be the name of the phone from Settings -> General -> About -> Name and the password should come from the personal hotspot screen.
Now start the personal hotspot on your phone. The pi should automatically connect when connected by a usb to lighting cable or using wifi. After connecting, the pi should be assigned an ip somewhere in 172.20.10.x. You can run ifconfig on the pi to figure out which one. (I believe that you should be able to define a static ip here but haven't messed around with that yet)
From there, you can connect another computer to the hotspot and ssh into the pi using the 172.20.10.x ip or even ssh directly from the phone.
In my personal testing, latency over lightning is consistently low and I've used this on both a Raspberry Pi Two and Raspberry Pi Zero for streaming realtime mjpeg video from two cameras to a VR headset. In this scheme, the network is a fairly small source of the 100ms or so latency. The experience is not Vive quality of course, but it is still usable and the iPhone + Pi combo provides lots of fun hacking opportunities
It's possible to do this with Mfi.You can run usbmuxd service on your Raspberry Pi. The usbmuxd will transfer the USB data into socket packets. Your iOS App also need to implement the same protocol to rx/tx the data from/to your Raspberry Pi.
David House has already made this work. https://github.com/davidahouse/PiTalk

cellular modem data session via "ethernet" adapter?

Most USB cellular modems present as a composite device containing (amongst other things) a modem and a network adapter. The latter shows up under the "LAN or High-Speed Internet" heading in Network Connections (and under Network Adapters in Device Manager).
I know how to initiate a data session on the modem interface using standard AT commands, but I am looking for information or documentation on (programmatically) using the network adapter.
My modems are a ZTE MF626i and a Sierra Wireless USB 301. I would happy with documentation that was either general in nature or specific to these modems.
Edited to add: I'm using Windows XP, so no Mobile Broadband API.
Assuming you're using Windows 7 or 8, you can use the built in Windows interface.
Use the VID and PID to identify the device amongst the Windows Network Adapters (find the VID and PID manually by inspecting the network adapter properties in Windows Device Manager).
Once you know the device, you can get the Windows device id programmatically.
Then use Windows Mobile Broadband API together with the device id to make data connections via the network adapter.
http://msdn.microsoft.com/de-de/library/windows/desktop/dd323269(v=vs.85).aspx

capture router packets using wireshark

i have two devices connected wireless on the same router. the one is my pc and the other is the smartphone. is it possible that, if i have instal the wireshark on the pc to capture the data/packets that the smartphone is sending and receiveing to a certain server which i know its ip? my pc has windows 2007 and the smartphone is an android device if its makes any difference
i try to install the shart for root on the android device but it is not working due to that my android is not rooted, and i don't wont to lose everything from my phone in order to root it
You can try using Cain & Abel. It will capture packets from your smartphone to router. To explain a bit, C&A will do ARP poisoning- meaning all the devices on your wireless network will assume that your desktop is the new router and all the incoming/outgoing traffic will go through your desktop. In this way you can capture the traffic on your phone without rooting it.
I hope this helps.

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