Three-pole telephone plug

The three-pin telephone plug is a connector used primarily in traditional telephone systems in Italy. This type of plug was the standard before the introduction of RJ11 sockets and is still used in many homes and offices to connect landlines or devices that require an analog telephone connection.

Main features:

• Type: Italian three-pole plug (also called "comb" or "telecom Italia").
• Configuration: 3 main poles for telephone signal transmission (line, ringer and ground).
• Compatibility: Can be used with standard Italian three-pole sockets.
• Material: Usually insulating plastic with metal contacts to ensure a good connection.
• Standard Size: The pin has three teeth aligned horizontally with a fixed distance.

Common usage:

• Connecting analog telephones to walls with three-pin sockets.
• Adapters to convert the connection from three-pin to RJ11, used in modern modems/routers.
• Alarm systems and remote control devices that require connection to the traditional telephone line.

Adapters and conversions:

Since modern telephone sockets use RJ11 connectors, 3-pin to RJ11 adapters are often used, which allow newer devices to be connected to traditional telephone sockets.

Electrical connections:

In the three-pole plug, the main contacts are:

1. LINE (L1): Input contact for the telephone line.
2. RINGER (L2): Used to activate the phone ringer.
3. EARTH (T): Present in some systems for safety and compatibility reasons.