Installation
2-5
1558A APS
• Loss of frame set to Enabled
• Loss of signal set to Enabled
In addition to setting the ROM configuration options, the
user must also manually configure the following options:
• LBO transmit level setting for both NET A and NET B
• DSX transmit level /distance setting for the DTE T1 port
• 1558A unit address (if optional 1559 manager is installed)
2.5.3
RAM Configuration
The 1558A can be optioned to boot all alarm and operating
parameters from the battery backed RAM at power up. To
configure the 1558A for this mode of operation simply set
S1 -7 to ON, and S1-8 to OFF. Note that the following unit
options must still be manually configured by the user:
• LBO transmit level setting for both NET A and NET B
• DSX transmit level/distance setting for the DTE T1 port
• 1558A unit address (if optional 1559 manager is installed)
2.5.4
Manager Configuration
The 1558A may be configured and controlled using the
optional 1559 APSM site manager. The manager, co-located
with one or more 1558A units (up to 56), provides both
local and remote access and control/alarm reporting to one
or more remote locations. When the 1558A has been config-
ured to ‘Boot from Manager’, the 1559 can access and
change all options except the following:
• 1558A Address
• 1558A LBO and DSX Levels
• Boot Mode (Switches, RAM, ROM, Manager)
To configure the 1558A to ‘Boot from Manager’, set S1-7
to OFF and S1 -8 to ON. For additional information con-
cerning the use and operation of the 1559 manager, refer to
the TxPORT 1559 APSM reference manual.
Unit configuration of the 1558A APS is now complete. The
final steps to complete installation is to perform the 1558A
preservice testing steps describe in the following sections.
2.6
Preservice Testing
The preservice test checks the operational integrity of the
1558A unit. The local pre-service testing is made indepen-
dently of any DTE or T1 connections. The end-to-end test-
ing requires that the T1 facilities be connected to the unit
and that the user has a T1 test set.
Figure 2 -2 on page 2 -6
illustrates the testing described in the following preservice
steps. Testing will verify:
• Path Integrity for Path A and Path B (local)
• Path Integrity for Path A and Path B (end -to -end)
The following T1 test equipment and miscellaneous cables
will be required to perform the preservice tests:
• Two T1 test sets (one required at each APS location)
• Two cables to go from the T1 test sets to the unit RJ 48
DTE connectors at both ends.
Before proceeding, the user should read and understand the
background information presented in the following para-
graphs concerning the basic operation theory of an APS ser-
vice (also refer to
Figure 3 -1 on page 3 -2
).
APS service is different from “normal” point-to -point T1
service. The 1558A APS unit accepts a single source signal
from the attached DTE equipment, verifies signal density,
duplicates the signal, and then transmits it on two T1 lines
(Path A, Transmit and Path B, Transmit). This duplication
and dual transmission is also done at the far end APS equip-
ment (if applicable).
In addition to the unique transmitting function performed by
the APS, the unit also performs a unique receiving function.
There are two identical signals being received from two T1
lines by the APS equipment (Path A, Receive and Path B,
Receive). The 1558A constantly monitors both of these lines
for satisfactory signal performance. In the event that the
present active receive line exceeds an alarm value, the APS
will automatically switch the service from the failed receive
path to the standby receive path. The active receive signal is
the path connected to the DTE equipment.
Once a path has declared an alarm condition from Errored
Seconds, Consecutively Severely Errored Seconds, Loss of
Frame, or Loss Of Signal, it will not be available for service
until a 2-minute interval has been detected that was com-
pletely error free. At that time, the path alarm circuitry will
be reset and then the path will be ready to accept service.
2.6.1
Path A Preservice Testing
Perform the following test steps to verify that the 1558A can
run error free data from the DTE port to the NET A port and
back (local loop test). The test setup for performing this test
is depicted in
Figure 2-2 on page 2-6
.
1)
Connect a T1 test set to the DTE RJ48 jack at the rear
of the 1558A unit. The test set should be configured to gen-
erate a T1 signal that matches the options previously set in
the 1558A unit (D4 or ESF, AMI or B8ZS) and configured
to supply clock to the 1558A.
