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Intercom telephone

What is Intercom?
What is the difference between a telephone and an intercom?
What are the types of intercom?
What equipment is required for an intercom?
How do you manufacture equipment for an intercom?
What are the various faults of an intercom?
What should you do in case there is fault in the intercom?
Who is the manufacturer of the intercom?
Who is responsible for maintenance of an intercom?
What is Intercom?

Wired and wireless systems are available.

It may be wise to set out by asking yourself the following questions for your home intercom plans:

* Do I want door intercom?
* Do I want entry video monitoring?
* Do I want room-to-room intercom?
* Do I want wholehouse broadcast intercom (paging) or handset intercom? Or the both?
* Do I want a wholehouse audio system?


Telephone Systemstechkeys

Telephone systems can be as simple as one phone with a single line or involve hundreds of phones and multiple lines. Many of the features used for years in business phones are now used at home. The following information is designed to make you aware of some of the options in today’s phone systems

Designing Your System

There are several considerations in a communications systems including:
* The type of communications you will need – Voice, data and /or video
* Do I want a DSL phone line, two analog phone lines or both DSL and analog lines?
* Do I want instead cable internet or dial-up internet?
* The number of users that will access a communications method at the same time.
* The current and future locations where you will need to connect a device.
* The number of incoming phone lines you will need.
* The types of features you will need.

How Do You Decide What You Need for a Home?
To decide what are the correct number of telephone lines and and what is the right equipment depends on several factors:ani-phoneringWHT
* Do you have a home office?
* Do you work from home frequently?
* How many people are there who need to use a phone at the same time?
* Do you use a dial up phone line to connect to the internet?
Frequently? For extended periods of time?
* Do you have a separate fax machine or an internal fax on your computer?

Technology now makes it possible to use one phone line in a variety of ways, such as different rings for different recipients, fax machines, and online service. Most home businesses need a minimum of two lines—one for personal use and one for business. You can use your personal line for outgoing calls so you don't tie up your business line for customers trying to reach you, and you can put your fax machine on your personal line.

To select the right phone equipment you will need to decide:
* Where you will be making or taking most of your calls
* Will you use the phone company for services such as voice mail or do you want to have that incorporated into your phone equipment.
* Do you want to access one or more lines on cordless phones?

How Do You Decide What You Need for a Business?

* Phone Systems Handsets- The number of telephodk3014SDLblk_thumbne system handsets is typically determined by the number of employees that have, or should have, their own phone. You should also include any reception or common areas (i.e., meeting rooms, lobby, etc.)
* Features and Services Desired- You need to determine if you desire call waiting, voice mail, call recording or other services. (See Common services below)
* Business Phone Lines (smaller systems)- The number of phone lines is equal to the maximum number of simultaneous inbound and outbound calls the company can make on its phone system. For example, a telemarketing company may need 40 telephone lines to service 60 handsets, while a manufacturing company may only need 15 telephone lines to service the same 60 handsets.
* Business Phone System Trunks (Larger Systems)- Phone system trunks typically refer to the total number of connections between your business telephone system and your phone carrier. Tie trunks are used to connect the phone systems between multiple offices. For most small to strata424medium US and Canadian businesses this is called a Trunk Level 1 or standard t1 line - Europeans use an E1 with slightly more capacity. For smaller companies that still need digital access for their business phone system, or the Internet, may use xDSL or a fractional t1 line. While, larger companies with heavy communications needs may step up to a ds3 or oc3 trunk.
* Business Telephone Systems Ports (PBX)- The maximum number of simultaneous telephone service connections that you will need to connect to your business telephone system. Telephone services include outside lines, inside extensions, voice mail, etc. the system will need to accommodate simultaneously.

What are Some Common Features of Communications Systems?

* Automated Attendant: Callers are greeted with a series of menu prompts (e.g., press 1 for Customer Services, press 2 for Sales) for reaching the department or extension they desire.
* Automated Call Distributor (ACD): Ensures calls are answered quickly and efficiently by routing inbound callers to group of employees with pooled extensions (i.e., support, sales, etc.). ACDs are generally used by sales and support groups to improve service levels and increase group utilization.
* Direct Inward Dial (DID): Provides company employees their own unique phone number so callers can reach them directly.
* Music On Hold: Callers listen to music while waiting on hold. * Promotion On Hold: Allows your company to inform callers about key company promotions, procedures or value propositions while they wait on hold.
* Interactive Voice Response (IVR): Allows callers to input and retrieve information from your company's computer database(s) via their touchtone telephone. IVRs are typically used by sales and support teams to improve their service levels and reduce support costs for high call frequency tasks (e.g., order status).
* Unified Messaging: Improves employee productivity by storing their email, fax, and voice messages in a single inbox accessible anytime anyplace via the phone, PC, Web or wireless device.
* Toll Fraud Equipment: A phone system monitor that reduces the risk of fraud and damage caused by hackers.
* Voicemail: Allows callers to leave personal messages if an extension is not answered.
* Voice over IP (VoIP): Reduces toll charges by allowing company employee's to use the IP network their PC is are connected to for placing and receiving phone calls. Also known as IP telephony or "VoIP".

What is Broadband?

While a standard phone line connection will allow data to be transmitted and received at speeds of 56 Kbps or less, broadband suggests speeds ranging from 128 Kbps to more than 1 Mbps over always-on network connections. The most common broadband technologies are cable and DSL. Both have the ability to group voice calls and other information into data packets carried on a single network.

How Can Existing Homes Accommodate All These Lines?

Most older homes are wired for two phone lines, later homes may be wired for three lines. More wired can be installed or equipment can be added to expand what can be done over the existing lines.

Can I Use Wireless Equipment To Meet My Comsmphonemunications Needs?

Yes and no. Wireless communications systems, such as wireless phones or wireless networks rely on available radio frequencies to operate. The technology is ideally used where there’s little chance of radio frequency interference, such as in large enterprises, airports, warehouses, and schools. But there can have major problems when interference is likely, such as in apartment buildings, neighborhoods with nearby houses, office parks with many small and independent businesses, etc. Future interference problems can come in two areas: (1) new wireless LANs installed by a neighbor, and (2) 2.4 GHz phone systems installed by a neighbor.

Interference caused by wireless LANs is just an annoyance, causing both networks to slow down. But the cordless phone systems designed for small businesses can completely shut down some networks – for the entire duration of phone calls.

What about Voice over IP?

VoIP is a technology used to send voice conversations over data networks using Internet protocols, such as Ethernet (or wireless Ethernet). As long as there is no other network traffic to interfere with voice services (and no outside interference), then good voice signals can get through, but interference is common and voice quality suffers. Ethernet is a contention-based network with no QoS, and wireless Ethernet adds the possibility of RF interference.

Should I Do it Myself or Use a Professional?

Depending on the number of features you desire it is possible to do you on phone or intercom installation. A professional can be of great assistance to you in selecting the correct equipment to serve your needs. The professional can also install concealed cabling which will look far more attractive then exposed cable used by most do it yourselfers

http://www.zenitel.com/en/Stentofon/Solutions/What-is-Intercom-/

Intercom

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Intercom system in the Pittock Mansion

An intercom (intercommunication device), talkback or doorphone is a stand-alone voice communications system for use within a building or small collection of buildings, functioning independently of the public telephone network. Intercoms are generally mounted permanently in buildings and vehicles. Intercoms can incorporate connections to public address loudspeaker systems, walkie talkies, telephones, and to other intercom systems. Some intercom systems incorporate control of devices such as signal lights and door latches.

Contents

Permanent systems

Traditional intercom systems are composed entirely of analogue electronics components but many new features and interfacing options can be accomplished with new intercom systems based on digital connections. Video signals can be carried as well as voice. Digital intercom stations can be connected using Cat 5 cable and can even use existing computer networks as a means of interfacing distant parties.

Many schools and office buildings now use audio / video systems to identify visitors trying to gain access to a locked building, and can be interfaced with the building's access control system.

Intercom systems can be found on many types of vehicles including trains, watercraft, aircraft and armoured fighting vehicles.

Portable systems

Portable intercoms are commonly used by special event production crews and professional sports teams. Performing arts venues such as theaters and concert halls often have a combination of permanently mounted and portable intercom elements. Motorsports race tracks often have both portable and permanent intercom stations mounted at critical points around the racecourse for use by race officials and emergency medical technicians.

Basic intercom system terms

  • Master Station or Base Station – These are units that can control the system, i.e., initiate a call with any of the stations and make announcements over the whole system.
  • Sub-station – Units that are capable of only initiating a call with a Master Station but not capable of initiating calls with any other stations (sometimes called slave units).
  • Door Station – Like sub-stations, these units are only capable of initiating a call to a Master Station. They are typically weather-proof.
  • Intercom Station – Full-featured remote unit that is capable of initiating and receiving party-line conversation, individual conversation and signalling. May be rack-mounted, wall-mounted or portable.
  • Wall Mount Station – fixed-position intercom station with built-in loudspeaker. May have flush-mounted microphone, hand-held push to talk microphone or telephone-style handset.
  • Belt Pack – portable intercom station worn on the belt. Requires a headset or handset.
  • Handset – permanent or portable telephone-style connection to an intercom station. Holds both an earpiece and a push to talk microphone.
  • Headset – portable intercom connection from a belt pack to one or both ears via headphones with integrated microphone on a boom arm. Connects to a belt pack.
  • Paging Signal – An audible and/or visual alert at an intercom station, indicating that someone at another station wants to initiate a conversation.
  • Power Supply – Used to feed power to all units. Often incorporated into the design of the base station.

Wiring intercoms

1980s MirTone intercom system

While every intercom product line is different, most analogue intercom systems have much in common. Voice signals of about a volt or two are carried atop a direct current power rail of 12, 30 or 48 volts which uses a pair of conductors. Signal light indications between stations can be accomplished through the use of additional conductors or can be carried on the main voice pair via tone frequencies sent above or below the speech frequency range. Multiple channels of simultaneous conversations can be carried over additional conductors within a cable or by frequency- or time-division multiplexing in the analogue domain. Multiple channels can easily be carried by packet-switched digital intercom signals.

Portable intercoms are connected primarily using common shielded, twisted pair microphone cabling terminated with 3-pin XLR connectors. Building and vehicle intercoms are connected in a similar manner with shielded cabling often containing more than one twisted pair.

Digital intercoms use Category 5 cable and relay information back and forth in data packets using the Internet protocol architecture.

Two-wire broadcast intercoms

Intercom systems are widely used in TV stations and outside broadcast vehicles such as those seen at sporting events or entertainment venues.[1] There are essentially two different types of intercoms used in the television world: two-wire party line or four-wire matrix systems. In the beginning, TV stations would simply build their own communication systems using old phone equipment. However, today there are several manufacturers offering off-the-shelf systems. From the late 1970s until the mid-90s the two-wire party line type systems were the most popular, primarily due to the technology that was available at the time. The two channel variety used a 32 Volt impedance generating central power supply to drive external stations or belt packs. This type of format allowed the two channels to operate in standard microphone cable, a feature highly desired by the broadcasters. These systems were very robust and simple to design, maintain and operate but had limited capacity and flexibility as they were usually hardwired. A typical user on the system could not choose who to talk to. He would communicate with the same person or group of people until the system was manually reconfigured to allow communication with a different group of people. Two-wire routers or source assignment panels were then implemented to allow quick re-routing. This reconfiguration was usually handled at a central location, but because voltage is used on the circuit to power the external user stations as well as communicate, there would usually be a pop when the channels were switched. So while one could change the system on-the-fly, it was usually not desirable to do so in the middle of a production, as the popping noise would distract to the rest of the production crew.

Four-wire broadcast intercoms

A modern four-wire intercom system capable of 272 sources and destinations manufactured by Telex Communications Inc.

In the mid-90s four-wire technology started gaining more prominence due to the technology getting cheaper and smaller. Four-wire circuit technology had been around for quite some time but was very expensive to implement. It usually required a large footprint in the physical television studio, thus was only used at very large stations or TV networks.

Wireless intercoms

For installations where it is not desirable or possible to run wires to support an intercom system, wireless intercom systems are available. There are two major benefits of a wireless intercom system over the traditional wired intercom. The first is that installation is much easier since no wires have to be run between intercom units. The second is that you can easily move the units at any time. With that convenience and ease of installation comes a risk of interference from other wireless and electrical devices. Nearby wireless devices such as cordless telephones, wireless data networks, and remote audio speakers, as well as structural features in your building, can all interfere. Electrical devices such as motors, lighting fixtures and transformers can cause noise. There may be concerns about privacy since conversations may be picked up on a scanner, baby monitor, cordless phone, or a similar device on the same frequency. Encrypted wireless intercoms can reduce or eliminate privacy risks, while placement, installation, construction, grounding and shielding methods can reduce or eliminate the detrimental effects of external interference. The United States and Canada have several frequency ranges for wireless intercom systems and other wireless products. They are 49 MHz, FM band (200KH – 270 kHz), 494–608 MHz, 900 MHz, 2.4 GHz, 5.8 GHz, and MURS (150 MHz).

Power line communication units that send signal over house wiring have been referred to as "wireless" intercoms. Though they are technically wired intercoms, they are based on existing wiring and thus require no additional wires.[2]

Loudaphone brand intercom station aboard RMS Queen Mary. The Loudaphone was specified for noisy environments such as aboard trains and trams and within a ship's engine room

Telephone Intercoms

Some telephones include intercom functions that enable paging and conversation between instruments of similar make and model. Examples include Panasonic model KX-TS3282W(/B), AT&T models 945 and 974, and TMC model ET4300.

A single device can add intercom functionality to multiple standard telephones on a common phone line, even of different makes and models. Installation effort is minimal, and is not vulnerable to the radio interference and security issues of wireless systems. The Add-A-Com Whole House Intercom for Standard Telephone Systems is such a device. Intercom paging is accomplished by sounding a distinctive ring from all telephones after any phone is taken briefly off hook. After paging, any number of phones may converse. The device temporarily disconnects the external phone line during intercom use, and reconnects when all phones are again on hook. During intercom use, an external call’s ringing signal can be heard in the earpiece.

See also

References

Wikimedia Commons has media related to: Intercom

Wireless intercom systems information

  1. ^ "Intercom Systems" page of GadgetShack.com.
  2. ^ "Wireless Intercom" page of IntercomsOnline.com.
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