Hi Roeland, >In the Hong Kong HKTA2003 specs in chapter 2.5 and 4.2 they are >speaking about shunt-wire -> does that mean they have tree wires in >the connector: A-wire, B-wire and the shunt-wire?
No doubt Hong Kong has the UK style of phone wiring; normal A&B (tip&ring) to the "master" socket at the customer premises. This master socket has a 1.8uF capacitor connected to the B wire, it's other end is on pin 3 of the socket. The phone cord plugged into this master socket (and all extensions wired off from it) carry 3 active wires (or 4 if you include an earth for "recall"). Compatible phones do *not* include any "ringer" capacitor; the ringer circuit is connected between A and the Shunt wire. When any phone is off- hook it places a "shunt" circuit between A and Shunt, normally consisting of a 100R and a pair of back-to-back zeners (3 - 5v). This shunt circuit prevents bell-tinkle on parallel phones during pulse dialling (and sharpens up the pulse-dial waveform, too). Now that Loop-Disconnect is almost obsolete it doesn't have much purpose but it's not broken, so they don't fix it. <g> Mike Electron Mobility Systems Net-Tamer V 1.11.2 - Registered
