Section 311-580-20B
030-101527 Rev. B
11
0407IBRB
own SPRM in order to provide performance information on the
T1 circuit at the point of the network interface. The R", U1"
and U2" bits of the 3115-80-generated PRM provide the addi-
tional performance information into the PRMs. The use of each
bit is given in the following paragraphs.
6.11.2.3 R Bit
Data is written to the R bit at a rate of 1 bit per PRM, or 1 bit per
second. Each new bit is written into the R bit associated with the
message for second t = T0". The R bit then shifts, second-by-
second, along with the other bits in the PRM until it is last seen
in the R-bit position for second t = T0 + 3". The 1 bit per sec-
ond patterns sent in the R-bit channel have the following
meanings:
000000000... No SPRM present or SPRM is disabled. This is
the status of the R bit when a CSU generates a
PRM.
111111111... SPRM added at point of generation of PRM. This
only applies when the NIU is generating its own
PRM, while in Frame Conversion mode.
10101010...
Internal hardware fault detected at point of inser-
tion of SPRM.
10001000...
SPRM added to PRM at intermediate point. This
mode applies when the customer equipment is
generating PRMs and the 3115-80 is modifying it
with additional information or when the 3115-80
is generating a PRM in Normal mode (frame con-
version disabled).
6.11.2.4 U1 Bit
This bit carries performance information in the DS1 signal re-
ceived from the network back to the network. This bit will be a
logic 1 if a condition is detected in the signal which would nor-
mally result in conversion of any bit in a PRM from 0 to 1. Each
U1 bit carries information for the same period as the 1-second
message in which it is embedded with such offset as is provided
by the transmission delay between the point of generation of the
PRM and the point of insertion of the SPRM.
- NOTE -
This bit defaults to zero for self-generated SPRMS.
6.11.2.5 U2 Bit
This bit carries performance information in the DS1 signal re-
ceived from the customer back to the network. This bit will be a
logic 1 if a condition is detected in the signal which would nor-
mally result in conversion of any bit in a PRM from 0 to 1. Each
U2 bit carries information for the same period as the 1-second
message in which it is embedded with such offset as is provided
by the transmission delay between the point of generation of the
PRM and the point of insertion of the SPRM. As a result of mod-
ifying a customer-generated PRM, a new Frame Check
Sequence (FCS) for the SPRM will be calculated and inserted
by the 3115-80.
6.11.3
SPRM/NPRM Mode
The SPRM/NPRM mode consists of both SPRM and NPRM
Performance Report Messages sent toward the network at 1-sec-
ond intervals. Detailed descriptions of SPRMs and NPRMs can
be found in Paragraphs 6.11 through 6.11.2.5.
Figure 9.
3115-80 Front Panel
B90-311580
126270
NIU-PM
C
P
E
M
O
N
TP1
TP2
F
A
C
M
O
N
PWR
LB
FLOS
CLOS
ESF
MAN
LB
B8ZS
7.
HARDWARE OPTIONS & FEATURES
The 3115-80 contains features and options located on the front
and side (PCB) panels, as described in the paragraphs below.
- NOTE -
Set any/all manual option switches prior to installing the unit.
- WARNING -
Before making
any
connections, verify power is off (including
removing the fuse at the fuse and alarm panel) and that any
and all plug-in units are removed from the shelf. Do not
install plug-in units until
all
shelf wiring is complete.
7.1
Front Panel Features
The unit contains several LEDs for a quick visual indication to
the status of the circuit, two bantam-type monitor jacks for trans-
mission path testing, a DB-9 connector with a female RS-232
interface for craft terminal access, and test points for measuring
span current. A description of each is provided below.
7.1.1
Monitoring Bantam Jacks
The 3115-80 contains two bantam jacks which monitor the T1
signal. These jacks are labelled FAC MON and CPE MON, as
shown in Figure 9.
FAC MON
Allows monitoring of the T1 signal being received
from the network
CPE MON
Allows monitoring of the T1 signal being sent to
the network
7.1.2
RS-232 DB-9 Connector
The 3115-80 contains a front panel, 9-pin, female, RS-232 DB-9
hardware connector which allows access to stored performance
