Verilink 1558D (34-00255) Product Manual - Manual (Page 21)

Operation 3-5 1558D APS CSU/DSU
line. If the user momentarily moves the switch to either the
A or B position and then returns the switch to the Auto posi-
tion, the 1558D will force service to the selected path (A or
B). If the user leaves the switch in the manual A or B posi-
tion, the 1558D will LOCK the service to this path and turn
on the LOCKED LED.
Placing the 1558D in a manually
locked mode prevents the unit from
performing automatic protection switch-
ing.
Path Status Alarm Indicators
The 1558D alarm circuitry is driven by the alarm parameters
defined by the user at time of installation. The user defin-
able alarm parameters are ES (errored seconds), CSES (con-
secutive severely errored seconds), LOS (loss of signal),
LOF (consecutive ESF errored frames). When any of these
alarm thresholds are met or exceeded, the ALARM LED
indicator (red) will be on for the path (A or B) that has
“failed”.
Path Status LOS Indicators
The 1558D LOS (loss of signal) Path A and B indicators
(red) will be ON when no T1 pulses are being detected on
the receive signal paths from the network. The definition of
loss of signal is no pulses for 175 bit times. The loss of sig-
nal state will be cleared when one or more data pulses are
detected on the receive path. After the pulses are detected,
the respective LOS indicator will be turned OFF.
Path Status Loop Indicators
The 1558D can respond to CSU loop/unloop commands
(both inband and FDL) and local or remote APS loop/
unloop commands. When a loop has been activated (Path A,
B, or DTE) the respective front panel LP LED indicator
(amber) will be ON. If no loop is active, the LP indicator
will be OFF.
Bantam Test Access Jacks
Bantam test access jacks and bridge/monitor jacks are pro-
vided to gain physical access to the T1 Path A (NET A), and
T1 Path B (NET B) facilities. The placement of the jacks is
depicted in Figure 4-10 on page 4-10. The function of these
jacks is described in the following table.
DTE Status Indicators
Three DTE port status LED indicators provide a visual indi-
cation of the present state of the SD (send data), and RD
(receive data) signals. Also, the TEST LED indicates if a
manual or soft loop has been initiated by the user. A brief
description of these items is described in the paragraphs
below.
DTE SD LED
This LED (green) will indicate that data transitions are
present on the TD lead (from the DTE equipment). The
LED will be on for a mark and off for a space condition.
The LED will vary in intensity depending upon the relative
number of marks or spaces present at any given time.
DTE RD LED
This LED (green) will indicate that data transitions are
present on the RD lead (to the DTE equipment). The LED
will be on for a mark and off for a space condition. The
LED will vary in intensity depending upon the relative num-
ber of marks or spaces present at any given time.
Table 3-B. Bantam Jack Functions
Path A /B Jacks Function
Transmit (Tx) to
T1 facility (lower
left jack)
Allows the user to gain access to the
transmit T1 path towards the T1 facility.
Inserting a test cord into this jacks dis-
connects the 1558D from the T1 facility
Receive (Rx) from
T1 facility (upper
left jack)
Allows the user to gain access to the
receive T1 path from the T1 facility.
Inserting a test cord into this jacks dis-
connects the 1558D from the T1 facility
Transmit Bridge
(BRDG) to T1
facility (lower
right jack) Allows the user to bridge/monitor the
transmit T1 signal towards the T1 facil-
ity. Note, test set must be set to the
bridge termination mode.
Receive Bridge
(BRDG) from T1
facility (upper
right jack) Allows the user to bridge/monitor the
receive T1 signal from the T1 facility.
Test set must be set to the bridge termi-
nation mode.
Figure 3-2 1558D Front View
SUPV STATUS
A LOCKED B
A
B
ALM LOS LP
A
SELECT
AUTO
PATH
B
STATUS
PATH
RX BRDG
TX BRDG
N
E
T
A
RX BRDG
TX BRDG
N
E
T
B
TxPORT
1558D
SD RD TEST
STATUS
PATH
NORM
LOOP
LL RL
APS CSU/DSU
PWR