Verilink 1558D (34-00255) Product Manual - Manual (Page 23)

Operation 3-7 1558D APS CSU/DSU
The 1558D will unloop after receiving a framed or
unframed repeating T1 signal of (100) for
≥
5 seconds.
When the unit unloops, the front panel Loop LED indicator
will go OFF.
ESF CSU Loop/Unloop
The 1558D will respond to industry standard ESF data link
loop/unloop messages. There are loop messages for a pay-
load loop/unloop and a line loop/unloop. Note that the
1558D will only respond to a data link loop command when
the path is in a standby mode (not actively carrying cus-
tomer T1 service). Also note that the front panel Loop indi-
cator will be ON whenever the unit/path is in a looped state.
Local/Remote Soft Testing
Using the provided user LAPS software, the user can gener-
ate both local and remote 1558D loop/unloop commands
and BERT testing commands. The various types of loops
and BERT testing are discussed in detail in Chapter 4, LAPS
Operation.
Rear Panel Connections
All APS unit wiring connections and option switches are
located on the rear panel of the 1558D unit. The function
and description of these items are discussed in the following
paragraphs (refer to Figure 3-3 on page 4-7 and the 1558D
Configuration Guide).
Alarm Terminal Strip
A four position screw terminal is provided to connect the
1558D unit to ground and to an external alarm device. All
connections to these terminals strip should be made using
26 -gauge wire, or larger. The purpose of these terminals is
briefly described as follows:
Ground: This terminal is used to connect the chassis
ground to an external earth ground.
Alarm Terminals (Com, NO, NC): These three terminals
are used to connect the APS unit alarm relay contacts to
external alarm alert equipment. The APS unit alarm relay
contacts can be wired as Normally Open or Normally
Closed. The contacts are rated at 2 amps @ 30 VDC. When
the APS is powered, the alarm relay is in the operated state
and the NO (normally open) contacts are open and the NC
(normally closed) contacts are closed.
Power
The 1558D operates from 115 volts AC. The maximum cur-
rent draw is ð80 milliamps. A six foot industry standard 3-
pronged AC power cord is shipped with the unit.
Option Switches SW1 - SW4
The 1558D has four banks of DIP switches mounted on the
rear panel (SW1 - SW4). These option switches allow the
user to configure the 1558D to meet the various applications
that the user may require (see Installation on page 2-1 for
additional information). The following paragraphs describe
these option switches.
O PTION S WITCH 1
This 8 position DIP switch will be used to configure the
APS functions of the 1558D. The function of each of the
DIP positions is described below. Note that the factory
defaults are shown in bold type.
Position 1 - This DIP will be used to set the APS card func-
tion, Master/Slave. A unit set to Master can poll the far-end
for status and can generate commands to the far unit. Slave
units can only respond to commands coming from a Master
unit. They cannot generate messages or obtain status from
far equipment. Note that 1558 units are installed in pairs and
only one of the units can be configured as a master. The fac-
tory default is SLAVE.
Positions 2, 3, - These positions will be used to set the
BOOT mode for the 1558D (Switches, ROM, RAM). The
factory default is boot from switches.
Position 4 - This DIP will be used to set the ARM (Alarm
Relay Mode error parameters) function for the APS (ARM
from ROM/RAM). The factory default is ARM from ROM.
The ROM values are ES = 20, CSES = 2, LOS = Yes, and
LOF = Yes.
Position 5 - This DIP will be used to set the Framing Error
alarm, Enabled/Disabled. The factory default setting is LOF
enabled. When enabled, the 1558D will declare an alarm
condition when 32 consecutive frame errors have occurred.
Position 6 - This DIP will be used to set the Loss of Signal
alarm, Enabled/Disabled. The factory default is LOS
enabled. When enabled, the 1558D will declare a LOS
alarm condition when a T1 receive signal contains 175 bit
times of no data transitions. The LOS condition will clear
when one or more data transitions have been detected.
Figure 3-3 1558D Rear View
COM BUS NET B NET A
IN OUT
GND N.
O.
COM N.
C.
ALARM
S1 S2 S3 S4 ON
OFF
ON
OFF
V.35