Grups de fax

Reading time: 2 – 2 minutes

La tonteria més gran del món q a tot telemàtic li han
fet empollar algún cop però q quan ha d configurar un modem/fax
no recorda mai q ha d posar al seu software pq el fax ruli més o menys
bé, o sigui: com carai anaba tot això dels grups de fax, un resum
ràpid i sense masses tecnisismes:

Groups are ITU-T (International Telecommunications Union – Telecommunications
Sector) pre-defined standards for fax machine transmissions to ensure that fax
machines from one manufacturer can communicate with a fax machine from another
manufacturer.

G1 or Group 1 – Transmits an 8.5″ X 11″ page in around six minutes. It
conforms to ITU-T Recommendation T.2 (Q10).

G2 or Group 2 – Transmits an 8.5″ X 11″ page in around three minutes.
It conforms to ITU-T Recommendation T.3 (Q10).

G3 or Group 3 – The most common fax communication standard in the
world today. It transmits an 8.5″ X 11″ page in as little as 20 seconds. It is
a digital machine and includes a 9600 bps modem. Group 3 fax machines can
transmit over standard phone lines. Group 3 defines a standard resolution as
203×98 dpi and Fine resolution at 203×196 dpi. Group 3 uses Modified Huffman
(MH) encoding scheme.

G3 bis or Group 3 bis – An update to Group 3. It includes an image
resolution of 406 x 196 dpi and a transfer rate of 14,400 bps. Group 3 bis can
transmit to another Group 3 bis machines at approximately twice the speed of
Group 3.

G4 or Group 4 – The latest fax communication standard in the world. It
defines the standard for fax transmission on a digital channel at 64Kbps. It
takes only 8 seconds to transmit a 8.5″ X 11″ page using G4 over an ISDN line.
Unfortunately, the availability of ISDN networks within United States is quite
low when compared to Europe and parts of Asia.