autorun.inf a simple text file which tells Windows that what application or program it needs to start automatically

This is specially used in removable USB disks and CD/DVD disks, so that the removable disks are able to automatically load the desired program

autorun.inf viruses generates a autorun.inf files in every disk of the system and whenever you open the disk it tries to execute the virus , They usually spread from external USB thumb drives

How to delete autorun.inf

To delete autorun.inf you need to reboot your PC to Safe Mode Command Prompt Only

When the DOS prompt appears , change to the root of the Disk drive
e.g for C drive you should do

c:
next step is to un-hide the autorun.inf file
execute the command
ATTRIB -H -R -S AUTORUN.INF
Finally delete it by the command
DEL AUTORUN.INF

So now you have deleted autorun.inf from C drive, do the same for other disk partitions in you PC

If you want to delete autorun.inf from a removeable or USB drive than you don’t need to boot into the safe mode, you can execute the above commands directly from CMD prompt or it would be even better if you just format the USB and get it cleared from all menaces

There are three common ways of transferring DTMF in SIP Or VoIP

1) SIP INFO Messages
This is the out of band method (out of band means that the DTMF messages are not carried within the media stream i.e. the RTP and carried separately
Its format is very simple, just in the body of INFO message the pressed DTMF digit is mentioned along with a duration for the DTMF signal

2) In Band DTMF transfer

As the name says, in this method the DTMF tones are carried in the media stream or RTP codec. This is a very crude method, DTMF is carried just a normal voice and we have no control over the DTMF , we can’t see it or decode it using wireshark or any other protocol analyzer
The optimized voice codecs like G729, GSM and G723 which used limited bandwidth face lot of problem in transferring in band DTMF
Due to limited bandwidth DTMF signals do not properly get transferred and receiving party is not able to decode them
To overcome this problem the 3rd method was devised


3) DTMF in RFC 2833

Via RFC2833 basically defined a new payload which has been created specially for carrying DTMF tones
So that DTMF is not dependent on the codec which has been made for voice but has its own optimized codec
Support for RFc 2833 is shown by the SDP rtpmap telephone-event

You can use VoIP to make phone calls using any of the below methods

1) You can use an analog telephone adaptor (ATA) to place a call. The ATA allows one to connect a standard phone to the computer through an Internet connection for use with VoIP.

2) VoIP calls can also be placed using an IP phone. These special phones resemble normal telephones, but instead of the normal RJ-11 phone connectors, they have the RJ-45 Ethernet phone connector. The IP phone connects directly to the router and includes all the necessary software and hardware to place a VoIP call directly.

3) A PC-to-PC VoIP call can also be placed using two computers, a microphone and a sound card. These calls are very cheap and usually free, like you can use skype for free skype to skype calling from PC.

For all of the above you will need an account from a VoIP service provider like Skype