Phone Line Simulator SP2One of methods to communicate with the controller if distance exceeds 15 meters (also connecting two computers to transfer files at significant distances) is by means of a direct modem to modem connection. The only thing necessary for a reliable connection of this type is a "Phone line simulator", a device to provide simulation of a telephone line, supplying the line current that modems are designed to work with. For these purposes, a very simple circuit will do the job. It is connected between two telephone modular jacks, and the two modems plug into the jacks.
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Phone Line Simulator SP2
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SP2 Basic Circuit
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SP2 Electronic Circuit
WARNING: RST is not responsible for any damage caused by connecting to SP2 power supply unit (or any other devices), which have different specifications as recommended by RST. Standard adapter +7.5V (300 mA) is recommended for SP2.