Distortion on exterrnal Door Station using DM02

[slychiu]

Problem;
An external door station eg Fermax, DP03X, DS01 connected to DM02 Door station Interface module has high distortion on the external door station speaker  but is clear on the inside keypad or telephone

Solution
This may be caused by the incorrect setting of the J5 shunt on the DM02. J5 should be shunted only if connected to a DP03X (not DP03) in order  to turn on the DP03 red LED when the inttercom is in use. The DP03x will NOT operate well  if J5 is not  shunted. For all other door stations (Fermax or DS01) leave the shunt off.
The DM02 manual already states that J5 should be shunted only for DP03X but the consequences have been spelt out more clearly in the revised manual 1.0.8 at https://www.cytech.biz/Downloads/Files/169/DM02man.pdf

[slychiu]

Slight correction to above post For DP03X, J5 MUST be shunted as this enables the Speaker amplifier as well as the MIC LED

[ndh]

Maybe shipped unshunted if this is the most common usage ?

[slychiu]

The purpose of the shunt is to cater for different products like Fermax, DP03X, DS01 etc so it is not always required to be removed.
The important thing for installers to do is to check what the correct settings should be for the installation, especially when there is a problem with distortion

[mindi65]

Thanks Chiu

Put it in bold and double size on next release of user manual. Some dum installers like me never read it carefully.

That was good finding. I had this problem after installing set of Farfisa/DM02, and been thinking about power/cabling and other problems.