telephone modem


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telephone modem

[′tel·ə‚fōn ′mō‚dem]
(electronics)
A piece of equipment that modulates and demodulates one or more separate telephone circuits, each containing one or more telephone channels; it may include multiplexing and demultiplexing circuits, individual amplifiers, and carrier-frequency sources.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

analog telephone adapter

A device that adapts a subscriber's analog telephones to a digital voice service from a VoIP, cable or DSL provider. Connecting to the modem, router or directly to the cable coming into the premises, the analog telephone adapter (ATA) delivers dial-tone, manages the call setup and provides the conversion between digital and analog voice. See IP phone and VoIP.


VoIP ATA
With this adapter, an analog telephone is connected to either a router (LAN) or the Internet (WAN) for VoIP service. For telco company (PSTN) backup, it includes an FXO port. See SIP and FXS. (Image courtesy of Grandstream Networks, Inc., www.grandstream.com)







Cable ATA
In this earlier Comcast cable example, the coax line was split between the ATA and cable modem. The ATA was wired to an analog telephone for voice, and the cable modem connected to the router for data. Newer Comcast gateways include the cable modem, ATA and wireless router in one device. See cable/DSL gateway.







Direct to Internet
Connected to the Internet via Ethernet to the local network, this ATA converts IP packets into analog voice (and vice versa) for the cordless base station. All other phones in this home are IP phones that also connect to the Internet. The ATA allows older equipment to co-exist with a new VoIP phone system. See VoIP.
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References in periodicals archive ?
Once connected to an online e-mail service, association staff members can access numerous resources from their desktop computers through a telephone modem. (A 14,400 bps, or bits per second, fax-modem is probably the best option today; one costs $100-$150 and normally comes with the appropriate software.)
A client whose mobility is severely impaired may gain access to the outside world with a computer that includes a telephone modem.
If you have a telephone modem, you'll find more sources of information
ADSL is a telephone modem technology that runs through traditional copper wiring, where - as broadband internet uses NTL' s fibre-optic cable TV network.
Both say there is a thirst in Arkansas for access to the Internet that is 27 times faster than a 56K telephone modem and allows Internet access simultaneously with talking on the phone.
The Zenith NetVision set, which includes a built-in 28.8 Kbps telephone modem, is expected to sell for $999.95 this fall.
"If any controller in the ICS goes down, the AC 9101 will notify maintenance personnel of the problem on their personal pagers over its built-in telephone modem, while ensuring that the other controllers in the system continue to function," said Joel Joseph, an electrical engineer and president of ECC Controls.
We have telephone modem tie-ins to the machines, if necessary, so we can troubleshoot them back home without having to send a person in the field to do that.
Since the late 1980s and 1990s, laboratory specialists used remote monitoring through telephone modems to check on the progress of features such as data acquisition.
When ACPE first began InterAct distance education courses over four years ago, the vast majority of our members were still connecting to the Internet by telephone modems, and CD-Roms were just becoming standard equipment on new computers for the home.
Chapter 8 discusses quadrature amplitude modulation, which is widely used in telephone modems. Chapter 9 describes nonconstant-envelope bandwidth-efficient modulation schemes, which improve power spectral density with little loss in error probability.