CANOGA PERKINS 2461 E1 Modem - Manual (Page 64)

EdgeAccess Universal Chassis System
This is done because the chassis backplane bus between adjacent odd and
even slots, ensures that when a redundant configuration is set up, data is
exchanged between the primary and secondary link.
Active Modem: The active modem is the modem transmitting the data payload. The following
conditions exist in the active modem:
• ELIM Relays are closed. The electrical signal is making it to the
composite.
• STA LED Solid green.
Inactive Modem: The inactive modem is in a state of readiness (QRSS BERT is on at payload
rate), waiting to begin transmitting the data payload, should an error be
detected on the active modem. The following conditions exist in the inactive
modem:
• ELIM Relays are open (but can be forced closed). The electrical
signal is not making it to the composite.
• STA LED is solid yellow.
• Rack mount unit will not send traps to the DMM.
• Payload QRSS pattern BERT is sent and verified at the local and remote
modems.
• The electrical interface should actually be in sync since the ELIM is
looping back the electrical signal when the relays are opened.
7.3.1 Standby Modem State and Activity
The standby modem (inactive modem) is not offline. In a redundant configuration, the inactive
modem runs a full data package to the Line Interface Unit. That data is continually being tested
via BERT and other loopback tests. The inactive modem is completely ready to begin
transferring data, should it become the active modem.
When a modem is switched from inactive to active (either manually or automatically) two things
happen:
1) Standby modes automatic BERT (Bit Error Rate Testing) will turn off.
2) The payload data will transfer.
2461 Modem User Manual 7-6