MultiModemISI Hybrid Series, ISIHP-2S/2U 11
Hardware Installation
ISIHP-2U LED Indicators
P LED Indicator
Indicates U interface status connection.
Controlled by NT-1, which converts S/T interface
(4-wire ISDN) to U interface (2-wire ISDN).
When U interface and S/T interface are NOT
active, LED remains off.
Flashes 8 times/second (8 Hz)U interface is
attempting to activate.
Flashes once/second (1 Hz)U interface is active;
S/T interface is not fully active.
Lit, not flashingBoth U and S/T interfaces are
active.
D LED Indicator
Lights when the ISIHP-2S/2U is turned on.
Flashes until SPIDs are verified with the central
office switch; then remains lit without flashing.
Indicates data link layer status.
LINE 2
P
D
D
LINE 1
P