PM4314 QDSX
DATA SHEET
PMC-950857
ISSUE 5
QUAD T1/E1 LINE INTERFACE DEVICE
TXRING[4:1] outputs. This differential driving scheme insures a small positive to
negative pulse imbalance. The drivers, with the step-up transformer, amplify the
output pulses to their final levels. The TIP and RING drivers also supply the high
current capability required to drive the low impedance output load.
A small, high-frequency negative-going spike may be observed on the falling
edge of the transmit pulse.This spike can be filtered out by using the optional
"snubbing" network shown in the following diagram. This snubbing network
should not be required when driving longer DSX-1 lines.
The XPLS includes a driver performance monitor to detect nonfunctional links.
Two monitor inputs, PM_TIP and PM_RING, are internally bonded to the XPLS's
own TXTIP and TXRING outputs. If no pulses are detected alternately across
the TIP or RING monitor points for 62 or 63 consecutive clock periods (the exact
number of clock periods, 62 or 63, depends upon the pattern of bipolar violations
and the line-build out), the monitored link is declared failed. The XPLS can be
programmed to produce an interrupt whenever the link monitor state changes.
The XPLS block provides Alarm Indication Signaling (AIS) generation capability
by generating alternating mark signals on the link when the TAIS bit is set high in
the XPLS Control/Status register (02DH, 06DH, 0ADH, and 0EDH). This AIS
generation may optionally be enabled when internal loopback modes are
enabled.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
48
PMC [ PMC-SIERRA, INC ]
