Telos Zephyr Xstream - Manual (Page 65)

USER’S MANUAL
Section 3: GUIDED TOUR of the HARDWARE 53
Parallel Inputs 0‐7
All inputs are specially treated to accept either a voltage (up to 24 VDC), or a closure to ground,
which may be provided by switches, relays, or logic outputs. The inputs are active low. In other
words, shorting the input to ground causes it to become true (i.e. "asserted").
A built in 1kΩ pull up resistor is provided so TTL outputs can be directly interfaced. See below
for a simplified schematic of the input circuitry.
+5 VDC
(30 Volts max)
INPUT
PIN 25
Parallel logic input circuit
t
DEEP TECH NOTE!
The Zephyr Xstream’s “universal” logic input circuit can be used with switch or relay
closures, voltage levels up to 24 Vdc, or logic outputs – either “totem-pole” or open-
collector.
The inputs can be transmitted to the far end Zephyr Xstream when using the Layer‐3 or AAC
coding mode. The inputs can also be used for local control functionality such as triggering Dial
Setups (Panic Dial). Refer to Section 11.5 (Detailed Menu Reference) for the menu selections
relating to these functions.