DESCRIPTION OF COMMUNICATION STANDARDS. INCLUDES MODEM & FAX.
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STANDARD NAME DESCRIPTION
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CCITT v.21 Standard for 300 bps. (FSK).
Bell 103J
Bell 202 Old standard for 1200 bps, half duplex. Leased lines.
CCITT v.22 Standard for 1200 bps. (DPSK).
Bell 212A
CCITT v.22bis Standard for 2400 bps. (DPSK).
CCITT v.26ter Standard for 2400 bps with echo cancellation.
Bell 208 Standard for 4800 bps. Used on leased lines.
CCITT v.27ter Standard for G3 FAX at 4800 bps with fall back to 2400 bps.
CCITT v.29 Standard for G3 FAX at 9600 bps with fall back to 7200 and
4800 bps. Also v.27ter/v.29 is used by CompuCom modems.
Half duplex. Reverse direction bps (slow?).
CCITT v.32 Standard for 9600 bps with echo cancellation. Fall back
to 4800 bps. Both direction simultaneously. (QAM).
CCITT v.32bis Standard for 14400 bps with echo cancellation. Fall back
to 12000, 9600, and 7200 bps. (TCM). Both directions
simultaneously.
CCITT v.33 14400 with fall back to 12000 bps. Used for what?
USR HST14400 US Robotics HST modulation. 14400 bps in one direction
and 450 bps in reverse direction. Fall back to 12000,
9600, and 4800 bps.
Trailblazer Proprietary and fast! Up to 18000 bps. ???
Hays V-Series Proprietary full-duplex 9600 baud. Hays its own CCITT LAP-B
error correction and its own scheme for data compression.
EIA Class2 FAX Fax standard called G2. ???
CCITT v.FAST Standard for 19200 bps or slightly higher. Uses echo
CCITT v.32bisbis canellation and is not FINALIZED. The first modems will be
available in late 1993. The name of the standard has not
been determined yet. It will have a much greater capability
to adapt modem speeds to meet existing conditions (more than
any existing modem). Theory sets a limit in the low 20000
bps range. This will probably be the LAST analog modem
standard.
NOTE: This prediction was incorrect. The V.FAST standards
(V.FC/V.34) are 28,800 BPS. V.FC was available in Early '94,
V.34 in Late '94.
Addendum:
V.FC 19200, 21600, 24000, 28800 BPS. Predecessor to V.FAST
(V.34). Engineered by Rockwell, Inc. Methods to be used
in ITU V.34 Standard.
V.34 (V.FAST) 19200, 21600, 24000, 28800 BPS. Ratified V.FAST standard,
based on V.FastClass (V.FC.)
ISDN Integrated Services Digital Network. This uses fiber optic
cable. It is currently available in larger cities within
3 miles (has been lengthen) of the central office. Available
in two flavors: Primary Rate Interface service and Basic
Rate Interface service. Basic, also known as 2B+D provides
users with two 64Kbit/sec channels for voice and data and
one 16Kbit/sec channel used by the carrier for call setup
and network management. The primary, also known as 23B+D
provides 23 64Kbit/sec channels and one 16Kbit/sec channel.
Some recent west coast subscribers will be paying a one
time $75 fee for a network connection device and $97 per
month for service, which includes two voice lines.
SMDS Switched Multi-Megabit Data Service. Uses fiber optics.
???
HDSL High-rate Digital Subscriber Link. Bell Labs and Bellcore
have recently developed this technology. It is capable of
carrying 1.5 megabits/sec over copper phone lines! Limited
to about 3 miles from the central office. Benificial since
it provides high speed data rate without running new fiber
optic cable to the customer. This is still in the labs.
The baud rate over the phone line means that more than two tones are used at
the baud frequency to achieve the bps rate. 4-DPSK means four tones...
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NAME DESCRIPTION OF ERROR CORRECTION AND DATA COMPRESSION
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MNP1 Hardware error correction.
MNP2 Hardware error correction.
MNP3 Hardware error correction. Strips off start and stop bits during
transmission over phone line.
MNP4 Hardware error correction. Fastest way to send compressed files.
Strips off start and stop bits during transmission. Also adapts
to line conditions.
MNP5 Hardware error correction and data compression (up to 2 time
compression on TEXT). Do NOT use on compressed files!
MNP6 Additional Universal Link Negotiation and Statistical Duplexing
to MNP5 service
MNP7 Additional Enhanced Data Compression with MNP4.
MNP8 Nothing available ???
MNP9 Additional Enhanced Data Compression with v.32 modems Also adds
Enhanced Universal Link Negotiation, which allows connection to
both MNP and non-MNP modems at the highest performance level.
MNP10 Hardware error correction and data compression. Special!
v.42 CCITT error correction. LAPM. Fastest way to send compressed
files. Strips off start and stop bits during transmission.
v.42bis CCITT data compression (up to 4 time compression on TEXT).
Uses a version of the Lempel-Ziv data compression algorithm.
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baud means Actual rate of symbols trasmitted per second.
bps means Bits Per Second.
MNP means Microcom Networking Protocol.
CCITT means International Telephone and Telegraph Consultative Committee.
FSK means Frequency Shift Keying.
DPSK means Phase Shift Keying.
QAM means Quadrature Amplitude Modulation. Combination of PSK and AM.
TCM means Trellis Coded Modulation.
LAPM means Link Access Procedure for Modems.
