Section 311-610-20B
030-101522 Rev. C
5
0509IBRC
3.1.3
FAC-to-CPE Regen
With FAC-to-CPE Regen enabled, the NIU will regenerate in-
put levels that have been attenuated from 0 to 30dB to a nominal
0dB DSX to the customer interface. The FAC-to-CPE Regen is
a selectable option that can be set remotely via TL1 or 16-bit
commands or locally via the craft terminal interface port. With
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.
3.2
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 signal
contains more than 128 consecutive zeros, a CPE-to-FAC path
Loss-Of-Signal condition is declared and the front-panel CPE
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 3116-10 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.
If FAC IN level is 0dB and CPE IN level is 15dB, and the
Binder Level selection is set for 22.5dB, the LBO circuit
would adjust itself to 7.5dB.
3.2.2.5
The resulting signal is then output over the FAC OUT
port toward the Telco Facility. To facilitate circuit testing, a
front-panel bantam jack (CPE BRG) provides bridging access to
the path.
3.3
Monitored Line Coding - AMI/B8ZS
The Monitored Line Code option determines if B8ZS octets and
8 consecutive 0’s are reflected in the Line Errored Seconds and
B8ZS Errored Second performance parameters. This option
does not effect the unit’s transmission path. When the Moni-
tored Line Coding is set for AMI, occurrences of 16 consecutive
0’s will be disregarded and occurrences of B8ZS octets will be re-
flected in the B8ZS Errored Count. When the Monitored Line
Coding is set for B8ZS, occurrences of B8ZS octets will be disre-
garded and occurrences of 8 consecutive 0’s will be reflected in
the Line Errored Seconds.
3.4
Monitored Framing - ESF/SF
The Monitored Framing option determines the framing refer-
ence that the performance monitoring (PM) section of the NIU
will use in it’s PM calculations. If the option is set for "ESF", val-
id ESF-framing bits and CRC-bits are expected. Note, the
setting of this option does not affect the unit’s ability to pass sig-
nal. That is, if this option is set to "SF", the NIU shall still have
the ability to pass ESF framed signals AND inject NPRM’s into
the ESF data-link - despite the fact that the PM section will be
reporting Severe Errored Frame events due to the framing mis-
match (i.e. Monitored Framing = SF, Actual FACILITY
Framing = ESF). This option can be set remotely via TL1 or
16-bit commands or locally via the craft interface.
4.
LOOPBACK FEATURES AND OPTIONS
Loopback can be used during maintenance and circuit trouble-
shooting to verify the integrity of the Telco DS1 facility up to, and
including, the NIU. Loopback, when activated, loops the entire
DS1 payload from the receive facility back towards the transmit
facility. Also, when the unit is in loopback the front-panel Loop-
back LED (LB) will be on, and a loopback timeout circuit, if
enabled, is activated. Figure 6 shows a simplified view of the cir-
cuit during loopback .
4.1
Facility Loopback
During Facility Loopback, the LB LED is solid yellow and the
receive T1 bit stream from the facility enters the NIU on the
FAC IN port. The signal is then routed through the loopback
