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Telecom Technical Q & A

Q. What is Acoustic Echo?
A. Acoustic Echo is the resulting echo when feedback is generated from the speaker to the microphone on any telephone, speaker phone or handset.
Q. What is an Analog Telephone Adapter (ATA)?
A. It is a device that converts analog voice signals to digital signals which can then be transmitted over the Internet.
Q. What is Attenuation?
A. It is the term used to describe the naturally occurring reduction or loss in signal strength when an analog or digital signal travels over a specific medium for long distances.
Q. What is a Backbone?
A. This is a high-speed network with a large capacity that connects major cities throughout the world.
Q. What is Bandwidth?
A. It is the amount of data that can be carried from one point to another in a given amount of time. It is usually measured on 1000 bits per second (kbps).
Q. What is a Baud?
A. It is one signaling element per second; this is not the same thing as bits per second.
Q. What is Cloud Communications?
A. It uses the Internet as a way to have users connect to host equipment at a remote location which then connects to the other users allowing telephone calls. This is also referred to as Hosted VoIP, Hosted PBX, Internet Phone Service and Cloud Phone Service.
Q. What is a Codec?
A. This is normally used in reference to converting analog signals to digital or digital signals to analog. It can be used in conjunction with compression software to compress and decompress these signals to varying degrees.
Q. What is a Channel Service Unit (CSU) / Data Service Unit (DSU)?
A. It is a hardware device, usually associated with a T1, that acts as an interface and converts data from a LAN to a WAN topology.
Q. What is Customer Premise Equipment (CPE)?
A. This is the term used for premise-based PBX hardware/equipment.
Q. What is a Customer Service Request (CSR)?
A. This is a document that is required for all telephone numbers that will show information that is tied to that telephone number, including services, billing, associated addresses and service orders.
Q. What is Data?
A. It is most commonly used to describe information, but when as a description for network topology it refers to all traffic other than voice.
Q. What is the Data Transfer Rate?
A. This is the amount of time it takes for a given amount of data to travel from one place to another.
Q. What is Dual Tone Multi-Frequency (DTMF)?
A. This is commonly known as Touchtone, it is the signal generated when you press a telephone’s touch keys that is sent to the telephone company. These signals are actually two tones of a specific frequency designed so that a voice cannot duplicate them. The ability for interactive telephone menus to work correctly across different networks and phone systems is due to the fact that DTMF tones are standardized and are uniquely linked to a number, # or * on the telephone keypad.
Q. What is a Dynamic Host Control Panel (DHCP)?
A. It is a communications protocol that lets networks administrators supervise and distribute IP addresses from a central point to each computer or device on a network.
Q. What is Direct Inward Dialing (DID)?
A. A feature offered for use with the PBX system which allocates a range of numbers that are connected to the client’s PBX.
Q. What is Echo Cancellation?
A. It is the process of eliminating echo from voice communication to improve the quality of the call. It is necessary because speech compression techniques and packet processing delays generate echo, of which there are two types, acoustic echo and hybrid echo. Echo cancellation improves voice quality in VoIP calls and also reduces the required bandwidth due to silence suppression techniques.
Q. What is Error Correction Mode (ECM)?
A. This allows for the receiving fax machine to request retransmission for a page where some errors were detected in the frames of that page. If the receiving fax machine is unable to receive an error free page the fax transmission may fail and the fax connection terminated. On networks with some packet loss, fax transmissions will routinely fail when ECM is enabled because of the low tolerance allowed for any packet loss.
Q. What is Fax over Internet Protocol (FoIP)?
A. Refers to the process of sending and receiving faxes through a VoIP network.
Q. What is a GR-909 Test?
A. It is standards based suite of electrical tests that have been adapted for the VoIP industry that test for such problems as unwanted voltage on the telephone lines, an off hook device keeping the line open, and even if no phone is connected on the line.
Q. What is an Integrated Access Device (IAD)?
A. It is equipment at the customer’s location that is used to convert digital signals back to voice. This is usually used in association with a DSL connection.
Q. What is an Integrated Services Digital Network (ISDN)?
A. It is a type of circuit switched telephone system designed to allow the digital transmission of voice and data over ordinary copper telephone wires.
Q. What is an Interactive Voice Response (IVR)?
A. It is a computerized system that allows a caller to select an option from a voice menu and otherwise interface with a computer system.
Q. What does Jitter mean?
A. Routers on the Internet can create slightly different times that individual packets take to travel from one point to another point. This variation is referred to as jitter.
Q. What is Latency?
A. This is the time it takes for a data packet to reach its destination.
Q. What is Line Echo?
A. This is an echo that is common in the PSTN and is created as a result of voice traveling over hybrids or 2 wire to 4 wire conversions.
Q. What is the Local Exchange Routing Guide (LERG)?
A. It is a database of the first 6 digits of a telephone number, updated on a regular basis that provides information for routing telephone calls over the PSTN. It also enables identification of what local company the number belongs to.
Q. What is Local Number Portability (LNP)?
A. It gives a US telephone customer the ability to retain their telephone number if they switch to another local telephone provider.
Q. What is a Mean Opinion Score (MOS)?
A. This is a numerical indication of the perceived quality of voice transmission after compression and/or transmission and is expressed as a number from 1 to 5. 1 is the lowest perceived audio quality and 5 is the highest perceived audio quality measurement.
Q. What is a Multimedia Terminal Adapter (MTA)?
A. This device is used to connect a traditional telephone to a cable line, converting analog voice to digital signals.
Q. What is Network Address Translation (NAT)?
A. It is an Internet standard allowing a local network to use one public IP address to connect to the Internet and a set of local IP addresses to identify each PC and device in the local network.
Q. What does Plain Old Telephone Service (POTS) mean?
A. This is the term used to describe traditional telephony service which runs over copper telephone wires.
Q. What is a Primary Rate Interface (PRI)?
A. This consists of 23 B-channels and 64 Kbps D-channel using a T1 line and can have up to a 1.544 Mbps service. Generally, it is a dynamic circuit that delivers both voice and data, giving preference for voice. When a channel is not carrying voice it is automatically allocated for data.
Q. What is a Private Branch Exchange (PBX)?
A. This is a private telephone switching system (PBX) that allows outside telephone lines from a telecom provider to connect to extensions within the office or building.
Q. What is the Public Switched Telephone Network (PSTN)?
A. It is the concentration of the world’s public circuit switched telephone networks; the combination of local, long-distance and international carriers that make up the worldwide telephone network.
Q. What is the Rate Center?
A. The geographic area used by local exchange carriers to set rate boundaries for issuing telephone numbers and for billing.
Q. What is a Request for Comments (RFC)?
A. It is one of a series of numbered Internet informational documents and standards.
Q. What is an RJ-45 connector?
A. It is an 8 wire connector used to connect Ethernet connections in computers, routers and other Internet devices.
Q. What is a Router?
A. This is a device that connects to at least two networks that determines the next network point to forward a data packet to. The decision of which way to send each data packet is based on its current understanding of the networks that it is connected to.
Q. What is the Real-Time Transport Protocol (RTP)?
A. This is an Internet protocol that functions for end-to-end network connections for applications that use audio or video.
Q. What is a Session Initiation Protocol (SIP)?
A. It is the protocol for initiating, modifying and terminating an interactive user session that involves elements such as voice, video and instant messaging.
Q. What are Silence Suppression / Comfort Noise Generation?
A. These are a means of increasing the number of calls supported by reducing the bandwidth for a single call. If speech is not present, the silence suppression is activated; this is done by removing and not transmitting the natural silence that occurs in a normal two-way connection. Comfort noise generation provides an artificially generated background noise that that reassures callers during silent periods that their call has not been dropped.
Q. What is Session Initiation Protocol (SIP)?
A. This is a signaling protocol for Internet conferencing, telephony and instant messaging. It is a request response protocol, dealing with requests from client and responses from servers initiating an interactive user session.
Q. What is Simple Transversal of UDP through NATs (STUN)?
A. This is a protocol for assisting devices behind a NAT firewall or router with the packet routing.
Q. What is SIP Trunking?
A. Typically used with a PBX, it uses VoIP to facilitate the connection to the Internet, where the Internet replaces the conversational telephone trunk. This allows a business to communicate with traditional PSTN telephone subscribers worldwide via a connection to an ITSP. SIP Trunking will save money by allowing services to an IP-PBX.
Q. What is a Softphone?
A. This is when IP Telephony software is used to allow end-users to send and receive calls over a computer or hand held PC device (PDA) using the Internet.
Q. What is a Switch?
A. This is a device that keeps a record of the MAC addresses of all devices connected to it. It then channels incoming data from any of multiple input ports to the specific output port that will take the data towards its intended destination.
Q. What is T.38 referring to?
A. This is the recognized standard for sending fax transmissions over an IP network in real time mode. Messages are sent as UDP or TCP/IP packets.
Q. What does Telephone Number Mapping (ENUM) do?
A. It takes a telephone number and links it to an internet address which is published in the DNS system.
Q. What is Voice Activation Detection (VAD)?
A. This is a software application, also known as silence suppression that allows the detection of the absence of audio for a specified amount of time to use techniques to conserve bandwidth. VAD can also be used to forward idle noise or comfort noise to a remote IP telephone or IAD so the listener does not think that the call dropped.
Q. What is Voice over Internet Protocol (VoIP)?
A. It is the routing of voice over the Internet (IP-based network) as digital packets rather than the traditional circuit-committed protocols of the PSTN. VoIP uses RTP to help ensure that the packets get delivered in a timely manner.