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Telefax G4 » History » Version 2

laforge, 03/03/2024 02:08 PM

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h1. Telefax G4
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G4 (Group 4) is a rarely-used version of the Telefax service which works only over ISDN.  Contrary to the much more commonlty used G3 (Group 3) for analog telephone lines, G4 does not include any Modem.  Instead, it natively uses digital transmission for the Telefax data over ISDN B-Channels.
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h2. B-channel captures
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* raw B-channel capture of a G4 fax that @manawyrm sent using RVS-FAX 3.0 on a Windows PC to the [[Canon_FAX-L260i]] of @laforge on 2024-03-01
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** attachment:isdntap-manawyrm-00493065022141-2152-20240301-193039-1-tx.raw
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** attachment:isdntap-manawyrm-00493065022141-2152-20240301-193039-1-rx.raw
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* soft-hdlc decode of the above capture (using "hdlcsync":https://gitea.osmocom.org/cellular-infrastructure/osmo-rbs/src/branch/master/hdlc/hdlcsync.c)
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** attachment:isdntap-manawyrm-00493065022141-2152-20240301-193039-1-tx.hdlcsync
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** attachment:isdntap-manawyrm-00493065022141-2152-20240301-193039-1-rx.hdlcsync
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