A redundant power source can be provided to PTP820C and S radios using the Dual DC Input POE – part no. N000082L022A. Two DC power sources can be connected to this POE at DC Power Port #1 and DC Power Port #2. When using the POE, only one Ethernet cable is required to go up the tower to provide both power and data communication to the radio. Data is then transferred from the POE to the switch using the GbE data port.
Some customers have asked if it would possible to add even more redundancy by running another DC power cable up the tower to the radio in addition to the two DC inputs on the POE. Unfortunately, this is not a viable option.
If a PTP 820 radio is powered by both a POE source and a direct DC source and at some point the DC source is lost, the radio may reset. This is because the POE is not a ‘Forced On’ device. Whether or not the radio will reset depends on the order in which the power sources are added to the radio. If the radio is ever powered by the DC input only and the DC input is later lost, even after POE is restored, the radio will reset.
Since it’s not possible to predict which power source will be lost, it is recommended to only use the two DC inputs of the POE device to provide power redundancy.
In the future we may offer a ‘Forced On’ POE device; however, there is no planned release date at this time.