Natcomm
Page 21
TROUBLESHOOTING AUDIO
If you are having trouble with AUDIO COMMUNICATION between the
DOOR PHONE and ANY TELEPHONES on your line, please follow the
procedure below.
Most problems are caused by site specific conditions. Through a process of
elimination, the source of problems can be determined and then rectified.
If you use ADSL on your telephone line, ensure that you have a High Quality
ADSL2+ filter fitted to your telephone line ahead of the DS2 Controller.
If you have recently updated your ADSL service, your old filter is unlikely to be
compatible with your new service, as ADSL2+ requires different filtering to the
ADSL2 service or the original ADSL1 service. If you are using FIBRE,
SATELLITE or CABLE for your Internet, you will NOT need an ADSL filter.
Your BALANCE POT, located on the back of the Door Phone may need
adjusting as described on page 13.
If you are still having audio quality problems, they can be caused by EMI
(Electro Magnetic Interference) from some Switch Mode Power Supplies and
some low end UPS units (Uninterruptable Power Supplies).
Switch Mode Power Supplies can be easily identified because they are very
light, due to the fact that they do not use a transformer. Many brands of these
power supplies are well known to generate high levels of EMI.
Please TURN OFF any SWITCH MODE POWER SUPPLIES located near
the DS2 controller (and its power supply) and test if the
problem is
resolved.
If the DS2 Power Supply is connected to an Uninterruptable Power
Supply, remove it and test if the problem is resolved.
If you are still having audio quality problems, then you may be picking up
interference (60 Hz power or other interference) from the telephone line input,
or the cable leading to your Door Phone.