3.7 Information about the Other Physical Cards
Power to the external sensor is provided from the EIO4 card and must be grounded through the EIO4 card
as indicated in the diagram below. A pair of "sensor" and "common" lines are connected to the EIO4 card
for each external sensor. The PBX detects input from the sensor when the signal is under 100 Ω.
Current Limit: 24 V DC/30 V AC, 1 A maximum