1-31
Cisco Metro 1500 Series Hardware Installation Guide
78-10588-03
Chapter1 Product Overview System Modules
If line B is the active line and you lock the RSM on line B, no switching takes
place. The communication is locked on line B. Any automatic switching to the
backup line (line A) is stopped.
If line B is the active line and you lock the RSM to line A, the RSM checks the
accessibility of line A. If line A is functional, the RSM switches the
communication to line A and holds the communication on this line. Any
automatic switching to the backup line (line B) is stopped. If line A is broken, the
RSM cannot be locked on line A.
At any time, the RSM can be switched from lock mode to automatic mode.
If neither line A nor line B is connected to the RSM or both lines are broken, the
red on LED blinks. Also, line A and line B LEDs are red as a visual signal to
check for disconnected lines.
The push buttons below the LEDs allow you to switch between automatic mode
and lock mode. Lock mode can be enabled for either line A or line B. If the lock
mode for one line is activated, the communication cannot be automatically
switched to the other line.
Lock mode can be enabled either for an active line or for a backup line. If the
activeline is locked, the communication cannot be switched to the backup line. If
lock mode is enabled for a current backup line by pressing the respective button,
the RSM checks the availability of the backup line and (if the line is in working
order) switches the communication to it, so that it becomes the active line and
locks it. Now, automatic switching to the backup line is impossible.
If the red on LED blinks and one of the A and B LEDs is red while the other one
is flashingred, this indicates two possible situations: neither line A nor line B are
connected to the RSM or both lines are broken. In this situation, the lock mode
can be activated once for testing purposes.
TDM4E Wavelength Channel Modules
The Cisco Metro 1500 series system can be equipped with an optional
time-division multiplexing 4 x ESCON (TDM4E) wavelength channel module.
The TDM4E uses TDM technology to provide a transmission capacity four times
higher than conventional WCMs. TDM technology allows you to combine 4
200 MB ESCON channels into one WDM channel, making optimal use of the
available fiber bandwidth.