Difference between SS7 and ISDN PRI

Both are similar in many ways, but SS7 is more powerful and core to the network. PRI is a subset of SS7.

ISDN PRI link must directly be connected to switch. It has no capability to route the call intelligently. Using SS7 every node in the network can be accessed. Nodes need not be connected directly, SS7 has got built in intelligence to redirect packets to the correct destination.

ISDN PRI is divided into Transport (B) channels and signaling (D) channels. Voice/Data is transmitted through the B channels and the associated signaling information is transmitted through the D channel. T1 has 23B and 1D channels. E1 has 30B and 2D channels.

SS7 allows to access the telecom companies databases, like the subscriber data, and other configuration information. Now a days most of the call routing is based on database information about the customer and the destination number.

An example for this would be, the credit limit approaching message that we hear when our credit limit is about to expire. Whenever a call is placed, subsriber information is looked up from the database the appropriate message is played or routed to the destination.

SS7 is used to interconnect the switches. Its not a consumer end protocol. Modern day switches convert SS7 to PRI before giving it to a vendor or a consumer.

The difference between PRI and SS7 is the kind of signaling that occurs. SS7 is the signaling network for telcos. Like ISDN, inter-telco signaling is OOB. However, SS7 links carry only signaling. And signaling is not solely related to call passing. LNP (Line Number Portability) transactions occur on this kind of link. You may think of ISDN as an IGP and SS7 as an EGP. ISDN is for processing calls between the telco and the customer. SS7 is for processing signaling, generally between telcos.

Encrypt Your Mobile VoIP Calls

Whisper Systems, announced the availability of it public beta Mobile Security Suite, with two applications for Encrypting SMS and VoIP calls on Android devices.

The VoIP application uses a new method of establishing a call using SMS as a signaling protocol instead of the initial SIP signaling, to overcome the SIP constant connection requirements.

The encryption is done using the well-known ZRTP protocol to setup SRTP stream between the 2 devices.

Here is how it works:

• The caller uses the RedPhone software normally to call any RedPhone number, the software will contact the RedPhone infrastructure, which will send an encrypted SMS to the destination RedPhone device.
• The received SMS will activate the RedPhone VoIP client on the destination, and the call will then start the normal sequence.

The 2nd application is TextSecure, which uses OTR encryption protocol with ECC.

Pretty neat idea, but it is only available in US for now, and only on Android devices.

Asterisk - Building a T1/E1 Loopback Connector

In order to perform a loopback test of the E1/T1 port, a loopback plug (also known as loopback connector or loopback cable) is needed. An E1/T1 loopback connector can easily be made using a single RJ45 connector and two 4-in (10-cm) wires.

Materials Needed:

• Unused RJ-45 plug
• Two strands of Category 5 (Cat-5) wire, each 4-in (10-cm) long
• Crimp tool for RJ-45

Procedure:

1. Insert one end of wire 1 into pin 1 of the RJ45 connector. Note: To ensure a good connection, make sure that each wire goes all the way into the end of the plug. Refer to Figure 1 for an example of an RJ45 pin layout.
2. Insert one end of wire 2 into pin 2 of the RJ45 connector.
3. Insert the other end of wire 2 into pin 5 of the RJ45 connector.
4. Crimp the connector.

Now you have a small loopback cable: a single RJ45 connector with pin 1 connected to pin 4, and pin 2 connected to pin 5.

After you install the loopback cable, zttool (or dahdi_tool) should show the span status as "OK" (green LED) on that specific span. If the status of that specific span is not "OK", then the E1/T1 loopback cable was made incorrectly (try another loopback cable), or the port is defective.

Smartphones to be used as hotel room keys

The key card could become a thing of the past after a hotel chain announced it would allow guests to access their rooms using their smartphones.

The technology, to be trialled at two hotels next month, would mean that guests could choose to avoid the hassle of checking in at the front desk.

Instead, they would download an application to their mobile device that would enable them to open their door simply by holding their phone to a sensor.

Testing will take place for at least 60 days at the Holiday Inn Chicago O'Hare Rosemont and the Holiday Inn Express Houston Downtown Convention Center, starting next month.

Bryson Koehler, an executive at InterContinental Hotels group, told USA Today: "The holy grail item for us is to simplify the room-key hand-off moment at the hotel.

"We don't need to burden people with additional items; it just clutters up their lives. The beauty of the smart phone is that they've already got it."

He said the technology would be compatible with most smartphones, including the iPhone, BlackBerry and Android phone.

If the trial is successful, it could be extended across the company's hotel network with sensors fitted to about one in five of each hotel's rooms.

Android 2.2...Just Image...

New king of tech: Apple overtakes Microsoft

New king of tech: Apple overtakes Microsoft

Flying cars may soon be a reality - Yahoo! India News

Flying cars may soon be a reality - Yahoo! India News

Boy fixes cracked iPhone screen for $21.95 (photos) | ZDNet

Boy fixes cracked iPhone screen for $21.95 (photos) | ZDNet

iPhone Asterisk project is a port of the Asterisk PBX to the Apple iPhone.

iPhone Asterisk project is a port of the Asterisk PBX to the Apple iPhone. It is still in early testing, but it complies, runs, and handles calls without issue. I am working on submitting my asterisk changes to Digium, but until then I've put a binary and source release below. To get the source release to complile, you need a working iphone and have the iphone cross complier working.

The first port of Asterisk 1.4.13 is done and working. All the code is released under the GPL v2.

Tested with iPhone firmware 1.0.2, not tested with 1.1.1.

How do I install Asterisk on my iPhone?

1) Make a new dir on your iphone (/usr/local/asterisk)

2) Copy all the files from the tarball into that directory

3) Execute /usr/local/asterisk/sbin/asterisk

4) Connect to the cli: /usr/local/asterisk/sbin/asterisk -r

5) Enjoy!


Download Here

Microsoft launches open source Outlook tool, SDK projects

Microsoft appears to be serious about making Outlook more accessible to open source developers.
On May 24, the Redmond, Wash software giant announced two new open source projects designed to complement its recently released technical documentation for Microsoft Outlook Personal Folders (.pst).

The two open source projects — dubbed .pst Data Structure View Tool and .pst File Format Software Development Kit — will make it easier for developers to access data stored in digital formats created by Microsoft Outlook and use that data in cross platform solutions.

Here’s how Microsoft described the benefit of the tool and SDK, which will simplify extracting the .pst data:
Developers can use these resources to more easily build solutions, including competitive products, that run on top of the .pst file format, unlocking data stored in .pst files in simple scenarios, such as extracting photos stored in .pst files to create an album, as well as more complex scenarios, including archive search, e-discovery and corporate compliance, and uploading data to the cloud.

In the spring, Microsoft released technical documentation for Office Outlook that makes it easier for developers to read and write data out of .pst files on any platform — whether or not Microsoft Outlook is installed on the desktop.

Previously, developers could use the Messaging API (MAPI) or Outlook Object Model to retrieve and use the e-mail, calendar and attachment data but it required Outlook to be on the desktop.

How Mobile Communication works?

Acronyms

Abis - Interface as E1 line
BSC - Base Station Controller
BTS - Base Transceiver System
EIR - Equipment Identify Register
HLR - Home Location Register
MS - Mobile Station
MSC - Mobile Switching Center
PCU - Packet Control Unit
Um - Air Interface
VLR - Visitor Location Register

Indian 3G auction closes, seven of nine bidders grab concessions

The oft-delayed sale of Indian 3G spectrum on Thursday, 20 May 2010 has finally been concluded, the Department of Telecommunications (DoT) has announced, revealing that the auction raised more than double the expected amount for the government. After 34 days of bidding, seven of the nine operators that had successfully applied to take part in the sale process came away with 3G licences, although no single operator was able to lay claim to a pan-India concession, with the most that any cellco managed to win being frequencies in 13 of the country’s 22 telecoms circles. Know More...

TV meets web. Web meets TV.

Google TV is a new experience made for television that combines the TV you know and love with the freedom and power of the Internet. Watch an overview video below, sign up for updates, and learn more about how to develop for Google TV. Coming Soon..

Gmail - Account recovery via SMS: Basics

f you forget your password, you can reset it using a recovery code which we send in a text message to your mobile phone. To receive this message, you'll first need to enable account recovery via SMS on your Google Account. Know More...

Hotmail's new security features vs Gmail's old security features

Microsoft’s revamped Hotmail, set to be rolled out in mid-summer according to the company’s press release, introduces several new security features, among which are full-session SSL, visual indication for trusted email senders, and improved password recovery mechanisms. Know More...

Asterisk 1.8 will make a difference

Asterisk has added a lot of new features and internal scalability and stability since 1.4. The 1.6.x releases are to me test releases to show and run practical tests with all of these changes. The core has changed, the API’s has changed and the internal PBX is practically new. We’ve proven scalability to over 10.000 calls on one server. We’ve proven interoperability with many, many products out there. We’ve changed the way we do development and we’ve moved Asterisk into the world of non-PSTN wideband audio. Of course, there’s a lot of more things we can do, but if we consider all of the changes since 1.4, Asterisk 1.8 LTS will be a really cool telephony toolkit.


Note: support for Asterisk 1.6.0 will cease in october 2010

SIP Session Description Codes

Session description
     v= (protocol version)
     o= (owner/creator and session identifier)
     s= (session name)
     i=* (session information)
     u=* (URI of description)
     e=* (email address)
     p=* (phone number)
     c=* (connection information - not required if included in all media)
     b=* (bandwidth information)
One or more time descriptions (see below)
     z=* (time zone adjustments)
     k=* (encryption key)
     a=* (zero or more session attribute lines)
Zero or more media descriptions (see below)
Time description
     t= (time the session is active)
     r=* (zero or more repeat times)
Media description
     m= (media name and transport address)
     i=* (media title)
     c=* (connection information - optional if included at session-level)
     b=* (bandwidth information)
     k=* (encryption key)
     a=* (zero or more media attribute lines)

SIP Methods from VoIP Info

SIP Methods

3CX VoIP blog � The Busy Lamp Field (BLF)

3CX VoIP blog � The Busy Lamp Field (BLF)

Ubuntu Login into Root prompt

Type "sudo su -" in your user prompt, so that you will be entered into root mode without prompting for root password for the first time.