Alpha Technologies USM2 - Manual (Page 21)

21
©2000 ™
704-587-B0-003 Rev.D
4. Signal Definitions
4.3 USM2 Signal Definition
This Section provides specific details of all signals (input and output) provided on the USM2’s XPDR and TMPR
Connectors when set up as an USM2 (Default setting).
Name: Common
Pin: J3-1
Signal Type: Ground reference / return
Referenced to: N/A
Description: Ground / return reference for ALL signals (analog, input & output) on the
USM. Same as pins J3-12 and J5-2.
Name: Auxiliary DC Out
Pin: J3-2
Signal Type: Power
Referenced to: Common (J3-1, J3-12)
Description: This pin provides power for transponder pull up resistors as needed. Auxiliary
DC Out is not intended to provide complete logic & transceiver power to the
transponder.
Parameters: Current drawn from this pin should NOT exceed 100mA under any circumstance.
Auxiliary DC Out is overcurrent protected by the Fuse, F1, which is a 100mA,
250V Slow Blow fuse.
How to test: Verify voltage on pin #2 is +5VDC, +15VDC, or +24VDC; as set by
configuration.
Name: Standby / Line Fail
Pin: J3-3
Signal Type: USM2 Discrete output
Referenced to: Common (J3-1, J3-12)
Description: This USM2 output indicates the state of the XM2 inverter.
Active Means: The XM2’s inverter is ON, and/or the line input has failed.
Active State: LOW
Inactive Means: The XM2’s inverter is NOT ON.
Inactive State: HIGH
How to test: With the XM2’s inverter ON, verify LOW on J3-3.














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Figure 4-1; USM2 Signal Schematic