Section 311-580-20B
030-101527 Rev. B
4
0407IBRB
5
15
CT1
CR1
7
13
41
47
55
49
CT
CR
FAC
IN
FAC
OUT
CPE
IN
CPE
OUT
T
R
T1
R1
Figure 4.
3115-80 Block Diagram Overview
FAC
MON
TO/FROM
TELCO
FACILITY
DIS
CPE
MON
FLOS
PERFORMANCE
MONITOR & LOS
DETECTOR
(CPE-to-FAC PATH - Z-A)
PERFORMANCE
MONITOR & LOS
DETECTOR
(FAC-to-CPE PATH - A-Z)
PERFORMANCE
REGISTERS
Note:
Switches shown are for illustrative purposes
only - options are provisioned electronically
CONTROL CODE
DETECTORS
FAC-to-CPE
REGEN
TO/FROM
CUSTOMER
INTERFACE
(CPE)
CLOS
CPE-to-FAC
REGEN
EN
DIS
EN
Provisionable/
Self-Aligning
LBO
22.5 dB
15 dB
0 dB
7.5 dB
AB15 dB
AB22.5 dB
LBO
15
7.5
0
the FAC-to-CPE Regen disabled, the receive transmission path
provides no net regeneration from input to output. In this case,
the NIU has a nominal insertion loss of 1.5dB.
3.1.4
FAC-to-CPE LBO
3.1.4.1
The fixed LBO circuit provides from 0 to -15dB of sig-
nal attenuation in 7.5dB increments. The FAC-to-CPE LBO is
a selectable option that can be set remotely via TL1 or 16-bit
commands or locally via the craft terminal interface port.
3.2
XMT Path: CPE-to-FAC (Z to A Direction)
The DS1 signal from the CPE enters the NIU via the CPE IN
port and is transformer coupled into the transmit path circuitry.
The transmit path is continuously monitored for loss of signal
and DS1 performance from the customer. If the CPE IN signals
goes below -30dBDSX for more than 150ms, a CPE-to-FAC
path Loss-Of-Signal condition is declared and the front-panel
CLOS LED lights solid red.
3.2.1
CPE-to-FAC Regen
When placed behind a multiplexer (i.e., fiber applications), the
unit functions as a T1 Extension Repeater and requires the CPE-
to-FAC Regen to be enabled. With FAC Regen enabled, the
NIU will regenerate input levels that have been attenuated from
0 to 30dB to a nominal 0dB DSX to the facility interface. The
CPE-to-FAC Regen is a selectable option that can be set re-
motely via TL1 or 16-bit commands or locally via the craft
terminal interface port. With the CPE-to-FAC Regen disabled,
the receive transmission path provides no net regeneration from
input to output. In this case, the signal is connected directly to
the CPE-to-FAC LBO circuit.
3.2.2
CPE-to-FAC LBO
3.2.2.1
LBO (Line Build Out) is an artificial line used to meet
T1 span and end-section design requirements. The 3115-80 pro-
vides a fixed LBO circuit as well as a self aligning LBO circuit.
3.2.2.2
The fixed LBO circuit provides from 0 to 22.5dB of sig-
nal attenuation in 7.5dB increments. The CPE-to-FAC LBO is
a selectable option that can be set remotely via TL1 or 16-bit
commands or locally via the craft terminal interface port.
3.2.2.3
As an alternative to the fixed LBO settings, the "Auto-
Binder" feature can be selected (AB15 and AB22.5). The
auto-binder option only introduces loss when necessary, auto-
matically protecting the network from mis-optioned customer
equipment - specifically, mis-optioned customer LBO settings.
3.2.2.4
At installation, the NIU/PM will have it’s "Auto-Bind-
er Level" circuitry optioned to match the circuit’s binder level
requirement .... e.g. -22.5 dB (AB22.5). The "Auto-binder Lev-
el" circuitry measures the signal level arriving from the facility
as well as the signal level arriving from the customer. Based on
these levels, the NIU/PM’s "Auto-Binder Level" circuitry will
automatically insert the appropriate amount of additional loss
required to ensure the customer’s signal arrives at the binder
group’s common termination point at the correct level. For a set-
ting of "AB22.5", a level of -22.5 dB is maintained. The
"Auto-binder Level" circuitry constantly monitors the input lev-
els from the network and customer and adjusts how much
additional LBO is required to keep the binder level at the neces-
sary level.
- NOTE -
The Auto-Binder Level" circuitry only introduces additional
loss when the customer fails" to meet the signal level require-
ments set forth by the RBOC. The additional loss is only inserted
when the customer’s signal threatens to interfere with other, adja-
cent T1 service by introducing crosstalk problems. Additionally,
sufficient hysteresis is provided to prevent the Auto-Binder" cir-
cuitry from oscillating in and out.
Examples:
If FAC IN level is 0dB and CPE IN level is 22.5dB, and
Binder Level selection is set for 22.5dB, the LBO circuit
would adjust itself to 0dB.
