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EXP-INTF (Expansion Interface Circuit Pack)
Issue 1 June 2005 1211
This is a 2-part connectivity test. In the first part of the test, a digital count is transmitted from the
cabinet of the EI circuit pack under test, through the EI circuit pack under test, out to its
lightwave transceiver. The connection then loops back into the lightwave transceiver, through
the same EI circuit pack again, and into the originating cabinet. If the test tone is detected by a
tone detector, the first part of the test passes. The path used for this part of the test is
represented in Figure 68: TDM BUS Lightwave Transceiver Looparound on page 1211.
In the second part of the test, a data packet is sent from the TN1655 Packet Interface circuit
pack to the EI circuit pack under test, the packet is looped back through the lightwave
transceiver and is sent back to the Packet Interface circuit pack. If the Packet Interface circuit
pack receives the same packet it transmitted, the second part of the test passes. If the entire
test has passed, the EI circuit pack, its backplane wiring, and the electrical portion of the
lightwave transceiver are healthy. The path used for this test is represented in
Figure 69: Packet Bus Lightwave Transceiver Looparound—PN only
on page 1212. The path
used for this test if the EI resides in a PN is represented in Figure 70: Packet Bus Lightwave
Transceiver Looparound—CSS and PN on page 1212.
When the EI circuit pack under test is in a PN, the data packet must also pass through the active
EI circuit packs and the active DS1 converter circuit packs (and the active SNI circuit pack(s) in
a Center Stage Switch system) of the active PNC link connecting the PN.
This test requires the EI circuit pack to ignore incoming data from its neighbor EI circuit pack or
SNI circuit pack. Thus this test will:
● Disturb any inter-PN connections that currently exist over the link provided by the EI under
test and its neighbor
● Disrupt signaling between the two circuit packs
Figure 68: TDM BUS Lightwave Transceiver Looparound
lightwave
To CSS or
Neighbor EI
TDMBUS (PN X)
Tone
Tone
Clock
Detector
EXP_INTF
transceiver