Sierra Wireless MP 875 Manual

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MP875 Modem User Guide

60 2130808

Digital output devices

Digitaloutputdevicesarethosethathaveonlytwostatesand

thestateiscontrolledbyasignalfromtheMPmodem.Any

devicethatistobeswitchedonandofffrom3GWatcher

wouldbeinstalledasadigitaloutputdevice.

Adigitaloutputcanbeconnectedtotwoofthepinsonthe

DB15HDconnector:Pins3and11.(Thesecanbeusedfor

eitherinputoroutput.)

Note: Before using the input/output lines, you must configure them as

inputs or outputs.

Typicallyadigitaloutputdeviceshouldbeconnectedbetween

Ground(pin10)andtheoutputport(Pin3or11).

Figure 6-3: Wiring for using Pin 3 (digital output) as an electronic switch. Pin

10 is Ground.

ThedigitalI/Oportsprovideopen‐collectoroutputtoa

maximumof500

mA.

Analog input devices

Analoginputdevicesarethosethatgenerateasignalof

varyingvoltage,based onthe stateofan instrumentorgauge.

Anexampleofananaloginputdevicemightbeasensorthat

detectsthevehicle’sspeed.

Ananaloginputcanbeconnectedtofourofthepinsonthe

DB15HDconnector:Pins7,8,14,and15.