This article introduces the methods of connecting ordinary telephone lines and crimping crystal heads, mostly referring to home telephones. Larger companies use group telephones and require system installation and debugging, which is not covered in this article for now. In addition, for ISDN users, due to the need for specialized boxes for ISDN access to telephones, they are now less commonly used and gradually phased out. Although ISDN has the advantage of digitization in transmission, it is not attractive for Mandarin voice transmission and may still have some effect in international voice transmission in the short term. Compared to others, traditional things still have more vitality.

Ordinary phone crystal head connection method

Phone sockets often use non international standard RJ11 (Registered Jack) phone crystal heads, which come in 4PIN or 6PIN options and are slightly smaller than RJ45 8PIN phone crystal heads. Also, do not plug the RJ11 interface into the RJ45 interface, as it may damage the RJ45 pins. In addition, some adapters use RJ45 8PIN crystal heads, and the connection sequence only needs to be in the same line sequence. The specific pins can be viewed from the protruding pins on the socket.

Due to the confusion in the use of RJ11, there are no regulations on cable colors, including red and white, black and yellow, red and blue, green and yellow. The specific colors may vary depending on the different cables connected. To confirm the input lines, only distinguish which two are available and cross connect them for testing. Even if there is a short circuit, it will not burn the telecommunications switch, and there is protection on that side.

A regular telephone line refers to a telephone input line that, when crimped to an RJ11 6PIN connector, only needs to be connected to the two pins in the middle of the crystal head (pins 3 and 4) without distinguishing the line sequence. The internal circuit of the phone will automatically switch.

The earpiece cable is a connecting cable between the telephone earpiece and the landline. The connector usually uses an RJ11 4PIN crystal head, and the wire sequence is 1-4, 2-3, 3-2, 4-1, which means reverse crimping (the crystal head should be placed flat with the front facing itself, and the wire sequence should be reversed).