Function Description - Grandstream Networks HA100 User Manual

Function Description

HA100 separates the external port into the corresponding internal ports (A and B). By default, port A is
always connected and port B is always disconnected, so only one UCM device is successfully connected
at one time. When the 2 UCMs connect to HA100 via port A and port B, the primary UCM uses the external
port on HA100 for data transmission. Additionally, the RS485 port on HA100 receives signaling from UCM
to achieve the switch between port A and port B.
If the internal port A on HA100 is connected successfully with the corresponding port on primary UCM, the
LED indicator for port A on HA100 will be in solid green. The primary UCM uses the external ports on HA100
to provide service. In this case, the LED indicator for port B on HA100 will not light up and the backup UCM
doesn't provide service.
If the primary UCM detects problem on itself, it will send signaling to HA100 via USB-to-RS485 cable.
HA100 will then switch the connection towards the backup server or in case the primary server is down by
any reasons, for instance power outage, the HA100 will then switch the connection from port A to port B,
making port B successfully connected and having backup UCM to provide service. In this case, the LED
indicator for port B on HA100 will light up in solid green while the LED indicator for port A will be off.
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HA100 User Manual