Signalling System 7 (SS7)

There are two essential components to all telephone calls. The first, and most obvious, is the actual content—our voices, faxes, modem data, etc. The second is the information that instructs telephone exchanges to establish connections and route the “content” to an appropriate destination. Telephony signaling is concerned with the creation of standards for the latter to achieve the former. These standards are known as protocols. SS7 or Signaling System Number 7 is simply another set of protocols that describe a means of communication between telephone switches in public telephone networks. They have been created and controlled by various bodies around the world, which leads to some specific local variations, but the principal organization with responsibility for their administration is the International Telecommunications Union or ITU-T.

Signalling System Number 7 (SS#7 or C7) is the protocol used by the telephone companies for interoffice signalling. In the past, in-band signalling techniques were used on interoffice trunks. This method of signalling used the same physical path for both the call-control signalling and the actual connected call. This method of signalling is inefficient and is rapidly being replaced by out-of-band or common-channel signalling techniques.

To understand SS7 we must first understand something of the basic inefficiency of previous signaling methods utilized in the Public Switched Telephone Network (PSTN). Until relatively recently, all telephone connections were managed by a variety of techniques centered on “in band” signaling.

A network utilizing common-channel signalling is actually two networks in one:

1. First there is the circuit-switched "user" network which actually carries the user voice and data traffic. It provides a physical path between the source and destination.
2. The second is the signalling network which carries the call control traffic. It is a packet-switched network using a common channel switching protocol.

The original common channel interoffice signalling protocols were based on Signalling System Number 6 (SS#6). Today SS#7 is being used in new installations worldwide. SS#7 is the defined interoffice signalling protocol for ISDN. It is also in common use today outside of the ISDN environment.

The primary function of SS#7 is to provide call control, remote network management, and maintenance capabilities for the inter- office telephone network. SS#7 performs these functions by exchanging control messages between SS#7 telephone exchanges (signalling points or SPs) and SS#7 signalling transfer points (STPs).

The switching offices (SPs) handle the SS#7 control network as well as the user circuit-switched network. Basically, the SS#7 control network tells the switching office which paths to establish over the circuit-switched network. The STPs route SS#7 control packets across the signalling network. A switching office may or may not be an STP.

SS7 Protocol layers:

The SS7 network is an interconnected set of network elements that is used to exchange messages in support of telecommunications functions. The SS7 protocol is designed to both facilitate these functions and to maintain the network over which they are provided. Like most modern protocols, the SS7 protocol is layered.



Physical Layer (MTP-1)

This defines the physical and electrical characteristics of the signaling links of the SS7 network. Signaling links utilize DS–0 channels and carry raw signaling data at a rate of 56 kbps or 64 kbps (56 kbps is the more common implementation).

Message Transfer Part—Level 2 (MTP-2)

The level 2 portion of the message transfer part (MTP Level 2) provides link-layer functionality. It ensures that the two end points of a signaling link can reliably exchange signaling messages. It incorporates such capabilities as error checking, flow control, and sequence checking.

Message Transfer Part—Level 3 (MTP-3)

The level 3 portion of the message transfer part (MTP Level 3) extends the functionality provided by MTP level 2 to provide network layer functionality. It ensures that messages can be delivered between signaling points across the SS7 network regardless of whether they are directly connected. It includes such capabilities as node addressing, routing, alternate routing, and congestion control.

Signaling Connection Control Part (SCCP)

The signaling connection control part (SCCP) provides two major functions that are lacking in the MTP. The first of these is the capability to address applications within a signaling point. The MTP can only receive and deliver messages from a node as a whole; it does not deal with software applications within a node.

While MTP network-management messages and basic call-setup messages are addressed to a node as a whole, other messages are used by separate applications (referred to as subsystems) within a node. Examples of subsystems are 800 call processing, calling-card processing, advanced intelligent network (AIN), and custom local-area signaling services (CLASS) services (e.g., repeat dialing and call return). The SCCP allows these subsystems to be addressed explicitly.

ISDN User Part (ISUP)

ISUP user part defines the messages and protocol used in the establishment and tear down of voice and data calls over the public switched network (PSN), and to manage the trunk network on which they rely. Despite its name, ISUP is used for both ISDN and non–ISDN calls. In the North American version of SS7, ISUP messages rely exclusively on MTP to transport messages between concerned nodes.

Transaction Capabilities Application Part (TCAP)

TCAP defines the messages and protocol used to communicate between applications (deployed as subsystems) in nodes. It is used for database services such as calling card, 800, and AIN as well as switch-to-switch services including repeat dialing and call return. Because TCAP messages must be delivered to individual applications within the nodes they address, they use the SCCP for transport.

Operations, Maintenance, and Administration Part (OMAP)

OMAP defines messages and protocol designed to assist administrators of the SS7 network. To date, the most fully developed and deployed of these capabilities are procedures for validating network routing tables and for diagnosing link troubles. OMAP includes messages that use both the MTP and SCCP for routing.

what is wireless

- Wireless is a term used to describe telecommunications in which electromagnetic waves (rather than some form of wire) carrythe signal over part or all of the communication path. Some monitoring devices, such as intrusionalarms, employ acoustic waves at frequencies above the range of human hearing; these are also sometimes classified as wireless.
The first wireless transmitters went on the air in the early 20th centuryusing radiotelegraphy (Morse code). Later, as modulation made it possible to transmit voicesand music via wireless, the medium came to be called "radio." With theadvent of television, fax, data communication, andthe effective use of a larger portion of the spectrum, the term "wireless" hasbeen resurrected.

Common examples of wireless equipment in use today include:

cellular phones and pagers -- provide connectivity for portable and mobile applications, both personal and business

Global Positioning System (GPS) -- allows drivers of cars and trucks, captains of boats and ships, and pilots of aircraft to ascertain their location anywhere on earth

Cordless computer peripherals -- the cordless mouse is a common example; keyboards and printers can also be linked to a computer via wireless

Cordless telephone sets -- these are limited-range devices, not to be confused with cell phones

Home-entertainment-system control boxes -- the VCR control and the TV channel control are the most common examples; some hi-fi sound systems and FM broadcast receivers also use this technology

Remote garage-door openers -- one of the oldest wireless devices in common use by consumers; usually operates at radio frequencies

Two-way radios -- this includes Amateur and Citizens Radio Service, as well as business, marine, and military communications

Baby monitors -- these devices are simplified radio transmitter/receiver units with limited range

satellite television -- allows viewers in almost any location to select from hundreds of channels

wireless LANs or local area networks -- provide flexibility and reliability for business computer users

Wireless technology is rapidly evolving, and is playing an increasingrole in the lives of people throughout the world. In addition, ever-larger numbersof people are relying on the technology directly or indirectly. (It has beensuggested that wireless is overused in some situations, creating a social nuisance.) More specialized and exotic examples of wireless communications and control include:

Global System for Mobile Communication (GSM) -- a digital mobile telephone system used in Europe and other parts of the world; the de facto wireless telephone standard in Europe

General Packet Radio Service (GPRS) -- a packet-based wireless communication service that provides continuous connection to the Internet for mobile phone and computer users

Enhanced Data GSM Environment (EDGE) -- a faster version of the Global System for Mobile (GSM) wireless service

Universal Mobile Telecommunications System (UMTS) -- a broadband, packet-based system offering a consistent set of services to mobile computer and phone users no matter where they are located in the world

Wireless Application Protocol (WAP) -- a set of communication protocols to standardize the way that wireless devices, such as cellular telephones and radio transceivers, can be used for Internet access

i-Mode -- the world's first "smart phone" for Web browsing, first introduced in Japan; provides color and video over telephone sets

Wireless can be divided into:
fixed wireless -- the operation of wireless devices or systems in homes and offices, and in particular, equipment connected to the Internet via specialized modems
Mobile wireless -- the use of wireless devices or systems aboard motorized, moving vehicles; examples include the automotive cell phone and PCS (personal communications services)
Portable wireless -- the operation of autonomous, battery-powered wireless devices or systems outside the office, home, or vehicle; examples include handheld cell phones and PCS units
IR wireless -- the use of devices that convey data via IR (infrared) radiation; employed in certain limited-range communications and control systems

TDMA technology

- TDMA (time division multiple access) is a technology used in digital cellular telephone communication that divides each cellular channel into three time slots in order to increase the amount of data that can be carried.
TDMA is used by Digital-American Mobile Phone Service (D-AMPS), Global System for Mobile communications (GSM), and Personal Digital Cellular (PDC). Each of these systems implements TDMA in somewhat different and potentially incompatible ways. An alternative multiplexing scheme to FDMA with TDMA is CDMA (code division multiple access), which takes the entire allocated frequency range for a given service and multiplexes information for all users across the spectrum range at the same time.

TDMA was first specified as a standard in EIA/TIA Interim Standard 54 (IS-54). IS-136, an evolved version of IS-54, is the United States standard for TDMA for both the cellular (850 MHz) and personal communications services (1.9 GHz) spectrums. TDMA is also used for Digital Enhanced Cordless Telecommunications (DECT).

what is analog system

- 1) In telecommunications, an analog signal is one in which a base carrier's alternating current frequency is modified in some way, such as by amplifying the strength of the signal or varying the frequency, in order to add information to the signal. Broadcast and telephone transmission have conventionally used analog technology.
An analog signal can be represented as a series of sine waves. The term originated because the modulation of the carrier wave is analogous to the fluctuations of the human voice or other sound that is being transmitted.

2) Analog describes any fluctuating, evolving, or continually changing process

What VoIP Can Do For You

Most companies are aware of the latest VoIP (Voice over internet) technology, but many don’t recognize the benefits of such technology and the positive impact that it can have on their organization.

There is a wide spread misconception about the benefits of VoIP.

If you ask many companies why they want this technology, they say they’re looking to eliminate their long-distance bills. While this might be financially compelling in some scenarios, the reality is that the true ROI of implementing this technology is not in the savings of telco bills.

If Not Cost Savings, What Is The Benefit?
Most VoIP solutions offer customized applications that can be designed specifically to meet the customer’s needs. No one industry benefits more from this technology than Call Centers themselves.

A poll of 105 Call Center Managers in 2006 by Interactive Intelligence showed that 73% plan to implement VoIP Technology in the future. 43% of these respondents said that improving customer satisfaction was the main concern when evaluating communication platforms.

Are You Building A Customer Service Powerhouse?
The truth is that by installing such technology and properly using it, you can help a call center establish a service powerhouse. This technology provides flexibility, innovation, and agility. The end results can provide a company with the ultimate customer service advantage–more profits, longer term customers, more revenue.

OK, so it is easy to claim all of the above, but if you are like me, you probably want to know how. Each call center is different, but there many applications that can help call centers across the board. Some of these applications are Interactive Voice Response, Unified Messaging, Skills Based Routing, Administration, and Outbound Dialing. Below I will briefly discuss the benefits of each application.

A Quick Menu of Options
■Interactive Voice Response (IVR) can offer self-service to customers 24/7. The IVR can be speech-enabled and can create an auto response for e-mail and web chat. [what kinds of companies do you find that don’t use this now that could? What are the characteristics of the type of company that this could fit?] This feature is popular in education, financial services, and companies that have customers who are calling in to check on their account.
■Unified Messaging today does more than just deliver your voicemails and faxes to your email. Today’s UM allows for Presence Management (ability to see on PC what other employees are doing) and enhanced call functionality (allows callers in to see where you are. By having unified messaging, employees work smarter, faster, and more accurately. Recording, chat, camp and conferencing functionality are just some of the features that allow that to happen. The bottom line is that every one of these features reduces cost, could increase revenue and increase customer satisfaction.
■Enhanced Routing features give a company the ability to route calls to locations or people based on skill level. This same routing technique can apply to e-mails, chat requests, and pre-defined media such as trouble tickets. Bottom line is it gets the customer in contact with the person they need to speak with—quickly.
■Administration of VoIP technology can be a Telecommunication Director’s dream come true. Gone are the days of paying for someone to change an extension or move a phone. Every aspect, from users to security access, of a VoIP communication system can be managed locally or remote. In addition, administration takes place from one interface. While every company is different (number of stations and people) one company saved over $55,000 in the first year. And many other companies have decreased their reliance on outsourced telecom service personnel.
■Outbound Dialing in the VoIP world allows call centers to optimize revenue opportunities by monitoring and analyzing real-time campaign performance. In addition, the outbound dialer can be set to an “agent-less” dialer. This dialer can be programmed to target specific demographics at certain times of the day or week.
The True Value For Your Company is Customer Satisfaction (and Revenue)
You can talk about the technology all you want—and many people do—but you need to know this: The true benefits, if properly designed and installed, can impact a call center significantly with higher levels of customer satisfaction and profitability.

It is imperative for the contact center manager(s) to get involved in the design of the technology before anything is decided upon.

Doing this will help ensure that the system is specifically customized to how it can best help your business