Hie There Everyone !!!
So this question is about cellphone companies and 3rd party companies being able to lock/unlock a cellphone to/from a particular network. My question is how do they do it especially/given that the mobile handset is located in a particular country ?? Also given that a phone is Network locked, what exactly is locked ?? Is it the firmware or it's software that basically prevents you from using another SIM Card ?? Is there any hardware available to unlock your mobile device on your own and at what cost ??
Thanks Very Much, I hope I made myself clear in this question.
Locking a phone on a particular network is up to recently a matter of sim locking the phone. This means the firmware does a test on startup is the inserted sim belongs to a specific operator. Most of the time there is an official procedure to unlock the phone you can ask to your operator if yous had been a subscriber "long enough". The ere are also unofficial procedures which can be applied if you have the right software you have to buy. In Africa it's a real business people do in the street.
Some spartphone vendors can also lock their phones is they have specific commercial agreements with the operator. They do it on their centralized servers. Unlocking in this case is tricky, or even impossible.
Related
I'm looking to establish a connection between my laptop and a remote PC in such a way that I can ping other devices connected to one of its network cards from my laptop.
That might be a little unclear- let me be more specific:
I am a PLC programmer, and my company just migrated to a brand of PLC that requires individual software licenses for each "station." So we're not going to be spending the money for the programming software at each location- instead, each technician will have a laptop, and he can physically visit whichever location needs troubleshooting.
However, that gets to be a lot of travel (international, in some cases), and I'm looking to come up with a way (using a VPN or something) so that I can connect to a PLC remotely.
Our setup is a Windows 7 Industrial PC at the customer's location with two network cards- one is hooked up to the customer's network (and the internet), and the other is hooked into the various PLCs, all with static IPs in the same range. I'm trying to minimize the amount of software I'll have to install/purchase for this project- we already use Teamviewer, but its VPN connection doesn't seem capable of accomplishing what I want (at least, I've never been able to manage a successful ping to one of the PLCs, no matter how much I mess with settings, and their support consists mainly of "buy our newest version").
I've seen lots of posts about this kind of stuff on the internet, but a lot of it seems directed to people who either already know how to set this stuff up and just want to know which software is cheapest, or it is specific to the brand of PLC (I'm using Lenze, which is not very common in english-speaking countries, or at least in america).
Anybody who has managed something like this- I'd really appreciate some sort of walkthrough, or at the very least some pointers in the right direction.
VPN is for TPC/IP communication. Whenever you need layer 2 from ethernet, you're stuck. I know that Step 7 TIA from Siemens can not find for PLCs via VPN. Explaination from support is that searching goes via layer 2. And this list can be made longer.
Most brands can now handle programming via memory cards. Just program local, write it to a memory card and plug it into your PLC.
Just contact the companies and see what they have to offer. The times are still here that PLC brands are fighting for customers. Let them do the work for you and enjoy. It works for our company. :)
Im in need of a solution, I basically require a way to print from a web page to a printer. But the printer needs to be standalone, either plugging directly into phone line, using a sim card etc. Does anyone know of a good solution for this?
It needs to be cheap to run, setup costs aren't that much of an issue, but obviously the cheaper the better.
If landline is okay, I believe the device you want is an antiquated piece of hardware called a "fax machine"
If wireless on a mobile network, the service plan is more of a cost concern than the hardware, though the two might be bundled together. For example, a company called bug labs is working on some kind of partnership with verizon for connecting their embedded linux device construction kit.
I am currently developing an embedded uP based appliance which can be remotely controlled via ethernet from a PC using its own SNMP manager software.
I have implemented all the private commands, i.e. using a private community password and under the enterprise tree OID (1.3.6.1.4.1.MY_PEN...etc) So from that point of view the unit is working OK.
What I am not too sure is whether the appliance should also respond to other SNMP OID branch queries (e.g. 1.3.6.1.2.1...or others ) Not for the benefit of my PC software, but for the benefit of other PC managers who may or may not want to know whether my device "exists" on the system.
I am aware this is not an essential requirement (my device doesn't need to be known to others) but perhaps there is an established "polite" requirement for SNMP agents in a network to be visible as such. In which case there may be a minimum subset of OID queries that such agents should at least respond to to any PC manager out there.
I cannot find anything about this on the internet, does such a thing exist?
Any comments (or at least a pointer to the "right" RFC as there are so many of them!
Thanks in advance
For devices that I've worked on, the MIB-II system group (sysName, sysLocation, etc) is usually implemented. Other standards are only implemented where a definite need exists. See RFC 1213.
I have few projects ideas that involve plugging a computer or an arduino to my landline phone (or just before it). For example, I would like to grab the caller ID sent when someone calls, do a lookup on the web or in an address book, and display the associated name on a LED screen.
The problem is that I can't find any resources on the protocols used for transmitting this caller ID, etc. I may have misused my google skills, so could anyone give me some pointers ?
I am particularly interested in all the protocols evolving around landline phones (caller ID forwarding/blocking, sending SMS, starting/ending a call, etc.). It is my understanding that while the long distance part (from central to central) is numeric, the signal reaching the phone on the customer side is still analogic. Is it true ?
The majority of public telephone networks (PSTNs) have a digital core (switch to switch) and an analogue edge (from the edge switch to your phone at home).
Business and large campuses (Hotels, Hospitals, Colleges - any large organization on a single or closely located sites) often will have a local phone system and switch (PABX) which will speak digitally to the edge exchange and which, increasingly, may speak digitally to the desk phones also.
There are actually a number of different standards in use for sending the CLI over the analogue circuit to your home phone depending on where you are and who your operator is - see the following link as a good starting point, although it is old and the links appear broken):
http://www.ainslie.org.uk/callerid/cli_faq.htm#Q_6
This one may also be useful:
http://www.tech-faq.com/fsk.html
What all would be the requirements for the following scenario:
A GSM modem connected to a PC running
a web based (ASP.NET) application. In
the application the user selects a
phone number from a list of phone nos.
When he clicks on a button named the
PC should call the selected phone
number. When the person on the phone
responds he should be able to have a
conversation with the PC user.
Similarly there should be a facility
to send SMS.
Now I don't want any code listings. I just need to know what would be the requirements besides asp.net, database for storing phone numbers, and GSM modem.
Any help in terms of reference websites would be highly appreciated.
I'll pick some points of your very broad question and answer them. Note that there are other points where others may be of more help...
First, a GSM modem is probably not the way you'd want to go as they usually don't allow for concurrency. So unless you just want one user at the time to use your service, you'd probably need another solution.
Also, think about cost issues - at least where I live, providing such a service would be prohibitively expensive using a normal GSM modem and a normal contract - but this is drifting into off-topicness.
The next issue will be to get voice data from the client to the server (which will relay it to the phone system - using whatever practical means). Pure browser based functionality won't be of much help, so you would absolutely need something plugin based.
Flash may work, seeing they provide access to the microphone, but please don't ask me about the details. I've never done anything like this.
Also, privacy would be a concern. While GSM data is encrypted, the path between client and server is not per default. And even if you use SSL, you'd have to convince your users trusting you that you don't record all the conversations going on, but this too is more of a political than a coding issue.
Finally, you'd have to think of bandwidth. Voice uses a lot of it and also it requires low latency. If you use a SIP trunk, you'll need the bandwidth twice per user: Once from and to your client and once from and to the SIP trunk. Calculate with 10-64 KBit/s per user and channel.
A feasible architecture would probably be to use a SIP trunk (they optimize on using VoIP as much as possible and thus can provide much lower rates than a GSM provider generally does. Also, they allow for concurrency), an Asterisk box (http://www.asterisk.org - a free PBX), some custom made flash client and a custom made SIP client on the server.
All in all, this is quite the undertaking :-)
You'll need a GSM library. There appear to be a few of these.
e.g. http://www.wirelessdevstudio.com/eng/
Have a look at the Ekiga project at http://www.Ekiga.org.
This provides audio and or video chat between users using the standard SIP (Session Initiation Protocol) over the Internet. Like most SIP clients, it can also be used to make calls to and receive calls from the telephone network, but this requires an account with a commercial service provider (there are many, and fees are quite reasonable compared to normal phone line accounts).
Ekiga uses the open source OPAL library to implement SIP communications (OPAL has support for several VoIP and video over IP standards - see www.opalvoip.org for more info).