Distance from Switch
If the telephone reception is very weak or the phone functions intermittently, it is likely that the unit has been installed too far from the switch (private branch exchange/PBX) or too many extensions have been installed on the line.
A maximum of five telephones may be installed on one line and the maximum distance from the switch to the telephone is 4.5 kilometres or 10,000 feet.
If more than five telephones have been installed on the line, the excess must be removed. Where the telephone is beyond the permitted distance, the unit must be installed closer to the switch or a power booster installed between the telephone and the switch.