Fax Standards (Itu-T Recommendations) - Dell 2135cn Service Manual

Printer
The printer prints image data from the control circuit onto the surface of paper. The principle is the
same as that of an ordinary printer in that black is applied to specified locations on the paper.

6. FAX Standards (ITU-T Recommendations)

International FAX standards (ITU-T recommendations) include G1 to G4. G1 to G3 use analog
telephone networks. G4 uses a digital telephone network (ISDN). G3 is the standard currently in
greatest use. FAXes conforming to Super G3, a recently added standard, are equipped with a fast
33.6kps modem and reduce transmission times to about half those of G3 FAXes.
Standard Year Issued
Group 1 (G1) 1968
Group 2 (G2) 1976
Group 3 (G3) 1980
Group 4 (G4) 1988
Version 2 2008.03.31
Minimum
Transmission
Maximum
Time for Single-
Resolution
Page A4
Document
Approx. 6 min. 100 x 100dpi
Approx. 3 min. 100 x 100dpi
Approx. 1 min
(14.4kbps)
600 x 600dpi
Approx. 3 sec
(33.6kbps)
Approx. 3 sec. 400 x 400dpi
6 – 16
Chapter 6 Principle of Operation (Fax)
Maximum
Transmission
Speed
First standard.
- Analog transmission.
(Analog) No band compression
technology
Analog transmission.
-
Band compression
(Analog)
technology adopted.
Connection to analog line
using FAX modem.
14.4kbps Image data in digital
(Super G3: format.
33.6kbps) Data compression.
Most common standard in
use.
Digital transmission.
Supported by various
64kbps
digital transmission
(Using ISDN)
services.
Halftone supported.
Features