Modular connectors 4P4C and 4P2C for handset cables (often erroneously referred to as RJ9, RJ10, and RJ22) 6P2C for RJ11 single telephone line 6P4C for RJ14 two telephone lines 6P6C for RJ25 three telephone lines 8P8C for RJ61X four telephone lines, RJ48S and RJ48C for four-wire data lines, RJ31X single telephone line with equipment disconnect, RJ38X (similar to RJ31X but with continuity circuit) Other connectors 50-pin miniature ribbon connector for RJ21X, used for up to 25 lines for multiline phones such as the ITT 2564, key telephone systems such as the 1A2 Key System, and PBX systems. International standards RJ11, by far the most common BS 6312, British F-010, French TAE connector, German National standards TDO-connector, Austria WT-4, Polish National Standard, also adopted in Russia as ШТР-IV (SHTR-IV) The Polish WT-4 plug is adopted in Russia as ШТР-IV (SHTR-IV) and has four metal pins and an additional fourth dielectric pin. The corresponding socket comes in two variants. The GTN-4 socket (РТШ-IV (RTSH-IV) in Russia) provides a 4 pin connection (in most cases, the two rightmost pins are used for connecting a single line). The GTNC-4 (РТШК-IV, RTSHK-IV) is a GTN-4 socket that has an additional circuit. The 5th plastic pin of the inserted plug disconnects a 1μF capacitor that otherwise closes the circuit of the telephone line when the plug is not inserted. This feature allows testing the line when the phone is not plugged in. The usage of a capacitor is mostly obsolete and GTN-4 sockets produced later reuse the capacitor compartment for an additional RJ11 socket. Legacy 600 series connector, Australia Protea, South Africa SS 455 15 50, Sweden and Iceland Telebrás plug, Brazil Tripolar plug, Italy BTicino 2021 (with or without line interruption), Italy (rare) List by country or territory This list covers only single-line telephone plugs commonly used in homes and other small installations; there are 44 different variations of plugs, including an Israeli version of BS6312 with different internal wiring of the pins, plus hard wiring to a junction box with no adapter. Special telephone sets use a variety of special plugs, for example micro ribbon for key telephone systems. See also Network interface device Power plugs/sockets by country References External links Telephone plug list—at Steve Kropla's World Wide Phone Guide How to install telephone wiring