User guide

19
Chapter 2 - Hardware Installation
I
O
A
D
D
R
LINE 1
LINE 2
8
7
6
5
4
3
2
1
PD
PD
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 ISIHI-2U is
turned on.
Flashes until SPIDs are verified
with the central office switch;
then remains lit without flashing.
 Indicates data link layer status.
The settings of the multiple DIP switch
unit on the mounting bracket determine
the base Input/Output address for the
ISIHI-2S/2U card. Input/Output
(I/O) addresses are used to route
information to and from the card.
ISIHI-2U LED Indicators
Figure 2-7. ISIHI-2U LEDs