Acoustic Coupler

An early variant of a modem is the acoustic coupler, which transfers digital computer datas over a telephone wire. The acoustic coupler is connected with a computer, e.g. on a RS-232 interface. The connection to the telephone network is directly used with the telephone earphone.

The data transfer rates of classical models (download/upload in baud): 110/110, 300/300, 1200/1200, 2400/2400 (full duplex) and 1200/75.

dataphon s21-23d

Packing of dataphon s21-23d

Data transfer speed:

• max. 300 bit/s; V.21 mode
• max. 1200 bit/s; V.23 mode
• Full duplex: 300, 600/75, 75/600, 1200/75, 75/1200 Baud
• Half duplex: 600/600, 1200/1200 Baud

Power:

• 9 Volt battery or accu
• External power supply 9-12 Volt, 40-50 mA
• over a V.24 interface

Switchs and controls:

• -/300/600/1200 Baud
• Inductive/acoustic coupler
• Switch Ans/Orig/Auto
• LED for answer mode
• LED READY
• LED originate mode
• LED send
• LED receive

Interface:

• V.24/RS-232
• Standard 25-Pin; ISO 2110
• DBT03 compatible for BTX

Dimensions: 27 × 8,5 × 5 cm (L × B × H)

Weight: ca. 400 g without batteries

dataphon s21-23d, BTX interface

dataphon s21-23d, switches and controls, RS-232 interface

Dynamics / Ascom

• Power: external power supply
• 300 Baud
• Contact 64 Software
• Connection with expansions port
• Control: Carrier
• Switchs: Speaker on/off ; Answer/Originate

• 

  Ascom Akustik-Koppler

• 

  Software

Radio Shack AC-3

• 110-300 baud
• Connection over RS232 (DSub-25, DIN)

Epson CX-21

Packinf of Epson CX-21

Data transfer rate:

• max. 300 Baud

Power:

• Battery (NiCd-Akku mitgeliefert)
• Power supply (4,8V/120mA)

Switchs and controls:

• Power on/off
• POWER LED
• Answer/Originate switch
• READY LED

Interface:

• Connection with V.24/RS232 (DSub-25)
• Full or half duplex

Dimensions: 30 × 9,5 × 7 cm (L × B × H)

Extras: Adjustable muffle

Epson CX-21

Links

Wikipedia: Acoustic_coupler