Data over Voice
Data over Voice ( DOV ) is a transmission method on analog telephone lines described in CEPT recommendation T / CD 01-13 . Above the frequency range of 300 to 3,400 Hz used for speech, a higher-frequency signal is fed in via a filter , which can be used for data transmission . Neither the voice transmission nor the transmission of charge pulses (16 kHz) is hindered.
Transmission frequencies ( FSK modulation):
- From the direction of the exchange: "0", space: 50 kHz, "1", mark: 60 kHz
- From the direction of the phone: "0", Space: 95 kHz, "1", Mark: 105 kHz
The separate frequency ranges also allow duplex transmission on a 2-wire line . The technology used enables a maximum transmission speed of 19,200 bit / s. According to the manufacturer, the range is up to 15 km with a wire diameter of 0.8 mm.
The German Federal Post Office introduced this technology briefly in mid-1991 with a few hundred devices. The reason was a lack of available lines in the former new federal states .
Basically, DOV can be compared with ADSL connections, which also allow data transmission above the voice band through the DSL splitter , albeit at a significantly higher data transmission rate .
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- CEPT: Recommendation T / CD 01-13 (Odense 1986) Engineering Requirements for a Voice Plus Data System, Edition of February 16, 1987
- Datentechnik, DOV-1X, DOV-1S, data via voice transmission module, operating instructions, 8828065d / 2.1, 05.91, L2806521
- Siemens, DOV-Modem 03, Data-over-Voice-Modem, description, commissioning instructions, Ref.-No.:A22581-F5104-A1-*-18
Web links
- DOV (data over voice) data over voice
- Description of DOV modem (English) ( Memento of 2 February 2004 at the Internet Archive )