Samsung DX-408 Installation Manual page 33

MPD/PRS Selection and Installation
This feature is for the DX-408 system only.
The DX-408 digital key system has four analogue trunk interface lines. Each of these
interfaces can be configured for either 12-KHz Metering Pulse Detection (MPD) or Polarity
Reversal Detection (PRS) by installing MPD or PRS Hybrids respectively.
For MPD functionality, insert an MPD Hybrid IC into the socket of each trunk requiring MPD
detection. The ports are set up for MPD use and no other hardware changes are required.
Trunk Port No.
Port #1
Port #2
Port #3
Port #4
For PRS functionality, insert a PRS Hybrid IC into the socket of each trunk requiring PRS
detection. Because the ports are set up for MPD operation it is necessary to solder a short
circuit across the capacitors to provide PRS functionality.
For example, if a PRS module is used in Port 2, a short circuit would need to be soldered
across C202 and another short circuit would need to be soldered across C203 to provide a
direct DC path to the PRS module in socket P201.
Trunk Port No.
Port #1
Port #2
Port #3
Port #4
12KHz /16KHz MPD Hybrid IC
P101
P201
P301
P401
PRS Hybrid IC
P101
P201
P301
P401
2-17
4.7nF/400V Capacitor
C102, C103
C202, C203
C302, C303
C402, C403
Short
C102, C103
C202, C203
C302, C303
C402, C403