Alpha Technologies EDSM - Manual (Page 14)

704-721-C0-004, Rev. D 14
Fig. 2-5, DIP Switch Location
Table 2-2, DIP Switch Settings
2.0 Connectors and Indicators, continued
2.5 DIP Switch
The on board DIP Switch (SW2) is used to confi gure the tamper polarity, provide RS-485
biasing per the ANSI/SCTE25-3 Specifi cation, and to enable programming. The factory
default switch settings are in the OFF position, with the exception of #3 in the ON position.
The tamper polarity switch allows for either a N/O or N/C switch to be used for enclosure door
monitoring. The ANSI/SCTE25-3 specifi cation requires the RS-485 signals to be optionally
biased to the Vcc and ground of the equipment. The programming mode switch setting is
used during programing of the micro controller. SW4 MUST be in the OFF position for normal
operation of the EDSM. For most transponders, SW3 must be in the ON position.
Switch # Position Description Function Description
1 OFF [default] Tamper Polarity Normally Closed
1 ON Tamper Polarity Normally Open
2 OFF [default] HMS Pullup/down
RS-485(+) Pulled Up
RS-485(-) Pulled Down
2 ON HMS Pullup/down No Bias
3 OFF HMS Line Balance No Balance
3 ON [default] HMS Line Balance
RS-485 lines tied through
120 Ohm resistor
4 OFF [default] Program User Mode
4 ON Program Programming Mode