Modem Block Diagram

Computer Modems

Modem Block Diagram

HERE is a brief summary block diagram of a typical computer modem.

Modem Primary Blocks :
Demodulator: Line receiver, A-D converter, digital steering logic,
Modulator: Digital steering logic, D-A converter, Line driver
Logic Control Block: Clock generator, Handshake logic, Tone detection, Data compression, error correction, Hayes command set, command interpreter, FAX modem plus Voice, PCMCIA

Modem Speeds
Baud Rate	Modulation Method
300 - 1200	FSK - Frequency Shift Keying
2400	QAM - Quadrature Amplitude Modulation
9.6 - 14.4	DPSK - Dual Phase Shift Keying
28.8 - 56.6	DPSK - Dual Phase Shift Keying (Dial-up, AOL)
128K	ISDN - Integrated Services Digital Network
380K	DSL - Digital Subscriber Line (SBC)
1.544M	T1
6M	Cable Modem - DOCSIS (Comcast)
16M	Backplane bus - VME Bus
44.7M	T3
155M	Sonet - Synchronous Optical Network
622M	ATM - Asnychronous Transfer Mode

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This Vaughns Summaries Communications Modem Block Diagram web page was updated on 2006-08-20.