PRELIMINARY
PM4318 OCTLIU
DATASHEET
PMC- 2001578
ISSUE 3
OCTAL E1/T1/J1 LINE INTERFACE DEVICE
9
FUNCTIONAL DESCRIPTION
Octants
9.1
The OCTLIU’s eight E1/T1 line interface units operate independently and can be configured to
operate uniquely. The octants do share a common XCLK clock input and internal clock
synthesizer; hence only a single CSU Configuration register is present. Additionally, all octants
share a common E1/T1B mode register bit to select between T1 and E1 operation.
9.2
Receive Interface
The analogue receive interface is configurable to operate in both E1 and T1 short-haul and long-
haul applications. Short-haul T1 is defined as transmission over less than 655 ft of cable. Short-
haul E1 is defined as transmission on any cable that attenuates the signal by less than 6 dB.
For long-haul signals, unequalized long- or short-haul bipolar alternate mark inversion (AMI)
signals are received as the differential voltage between the RXTIP and RXRING inputs. The
OCTLIU typically accepts unequalized signals that are attenuated for both T1 and E1 signals and
are non-linearly distorted by typical cables.
For short-haul, the slicing threshold is set to a fraction of the input signal’s peak amplitude, and
adapts to changes in this amplitude. The slicing threshold is programmable, but is typically 67%
and 50% for DSX-1 and E1 applications, respectively. Abnormally low input signals are detected
when the input level is below a programmable threshold, which is typically 140 mV for E1 and
105 mV for T1.
Figure 8 – External Analogue Interface Circuits
VDD
D1
L1
F1
TTip
1:n
T1
Z1
Z2
TXTIP
outB
inA
inB
center tap
R1
Z5
chassis gnd
outA
TXRING
L2
F2
TRing
RTip
gnd
Phantom Feed
Circuit or Vsupply
as required
ATB
VDD
F3
gnd
Z3
Z4
1:n
T2
RXTIP
outB
inA
inB
center tap
Z6
R2
chassis gnd
outA
RXRING
F4
RRing
One of Eight
T1 or E1 LIUs
gnd
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
35
PMC [ PMC-SIERRA, INC ]
