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Modem Specifications

The International Telegraphic Union (ITU), defines the standards.
The 'V.xx' is the spec number, the title is in bold, a description in plan text.
The term 'bis' refers to the 2nd version.





V.13: Simulated half-duplex (switched-carrier) control.

V.17: A 2-wire modem for facsimile applications with rates up to 14 400 bit/s

V.21: 300 bits per second duplex modem standardized for use in the general switched telephone network

V.22: 1200 bits per second duplex modem standardized for use in the general switched telephone network and on point-to-point 2-wire leased telephone-type circuits: Synchronous/asynchronous data transmission, full duplex over 2-wires, 1200bps.

V.22bis: 2400 bits per second duplex modem using the frequency division technique standardized for use on the general switched telephone network and on point-to-point 2-wire leased telephone-type circuits

V.26bis: 2400/1200 bits per second modem standardized for use in the general switched telephone network

V.32: A family of 2-wire, duplex modems operating at data signalling rates of up to 9600 bit/s for use on the general switched telephone network and on leased telephone-type circuits: Synchronous/asynchronous data transmission, full duplex over 2-wires, 9600bps (fall-back to 4800bps).

V.32bis: A duplex modem operating at data signalling rates of up to 14 400 bit/s for use on the general switched telephone network and on leased point-to-point 2-wire telephone-type circuits: Synchronous/asynchronous data transmission, full duplex over 2-wires, 14.4kbps, 12kbps,9600bps, 7200bps, 4800bps.

V.33: Synchronous data transmission, full duplex over 4-wires, 14.4kbps, 12kbps.

V.34: Synchronous/asynchronous data transmission, full duplex over 2-wires (2/4 lines, leased), 28.8kbps.

V.34+: A modem operating at data signalling rates of up to 33 600 bit/s for use on the general switched telephone network and on leased point-to-point 2-wire telephone-type circuits: Synchronous/asynchronous data transmission, full duplex over 2-wires (2/4 lines, leased), 33.6kbps

V.90: A digital modem and analogue modem pair for use on the Public Switched Telephone Network (PSTN) at data signalling rates of up to 56 000 bit/s downstream and up to 33 600 bit/s upstream: (56K) Synchronous/asynchronous data transmission, full duplex over 2-wires, 56kbps. The V90 uses Pulse Code Modulation (PCM).

V.91: A digital modem operating at data signalling rates of up to 64 000 bit/s for use on a 4-wire circuit switched connection and on leased point-to-point 4-wire digital circuits



Modem Standard Organizations

International Telegraphic Union (ITU), located at http://www.itu.int

{Modem Index}


Modem Interface IC Manufacturers

Analog Devices
{V.35 xceviers}

Cermetek Microelectronics Inc.
{Modem Modules, Low Speed / High Speed Modems}

CML "Consumer Microcircuits Limited"

Linear Technology
{V.35}

PLX Technology
{serial bridges with UART, PCI, PCIe, Parallel/Local Bus and USB Interfaces}

TI
{High-speed QAM modem chip sets}

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Related Component Manufacturers;
TeleCom Device Manufacturers
Memory Chip Manufacturers
Processor Manufacturers
Glue Logic Manufacturers


Modem Standard

Cable labs {Cable Modem Specifications}

Modem AT Commands {Jason John Schwarz}

Modem Pin-Out

RS232 Cables, Wiring, and pinouts

{Back to Modem Index}


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Modified 6/13/15
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