Transformer Circuit - Samsung SCX-4720F Service Manual

Summary of Product
4.8.3 Tel-Line Connection Circuit
• The Tel-Line Connection Circuit connects the fax machine to the PSTN using Tip and Ring terminals.
• Use Modular Plug : RJ-11C
• Arr1, Arr2 and Arr3 are protection components to prevent damage due to overvoltage surges, e.g. lightening.

4.8.4 Transformer Circuit

• The Transformer circuit is a line impedance matching circuit which matches the internal impedance of the fax machine
to the external -48Volt DC impedance of the PSTN system.
• The Transformer circuit insolates the fax machine electrically from the PSTN.
Service Manual
4-24
Samsung Electronics