User's Manual

Table Of Contents
3-10 Aviat Networks
Chapter 3. System Overview
With a Tx mute configured on the offline Tx, its Tx status cannot be monitored. A
solution to guard against this leading to a possible unreported standby Tx failure
situation will be available in a latter SW release. This will enable periodic activation
of the standby Tx for health monitoring purposes - it will be turned on, checked and
turned off again.
RFU and RFUv2
IRU 600v2 RFUs (RFUv2) incorporate a Tx switch control port (DIN5 connector) for
cable connection to the Tx coaxial switch.
Switch-port cables (two) are included with the Tx switch on IRU 600v2 MHSB/SD
ACUs.
The DIN5 switch connector is located where the RSSI BNC connector was positioned
on the RFU (V1).
On the RFUv2, RSSI access is provided on the front panel as meter test-probe points.
IRU 600 and IRU 600v2 Compatibility
Chassis dimensions and mounting points are identical. RFU (V1) can be installed in an
IRU 600v2, and an RFUv2 can be installed in an IRU 600 (V1). Similarly, the
installation space for ACU elements is identical.
Both IRUs are fully over-air compatible with like-for-like configurations. For example,
a 1+1 HSB IRU 600 (V1) may be linked to a MHSB IRU 600v2.
The RFUv2 is backward compatible with RFU (V1) in configurations supported by the
IRU 600 (V1). RFU (V1) is not compatible with RFUv2 in an IRU 600v2 except for 1+0
operation.
RFUv2 can be used in place of an RFU (V1) in an IRU 600 (V1) configured for 1+0 or
1+1 operation.
RFU (V1) can be used to replace an RFUv2 in an IRU 600v2 for 1+0 link applications
only. RFU V1 cannot control the Tx coaxial switch.
Both IRU 600 V2 and V1 versions are compatible within a chassis and within a hub.
There is one exception. Because the unit may not be set to a monitored hot stand by
configuration in combination with a V2 RFU. The combination of V2 and V1 RFUs only
works in a non-hot standby configuration.
Power Supply and Cooling
The high power RFUs are powed from the INU/INUe, and additionally via a separate
DC input on the RFU front panel. For more information see Power Supply.
Each RFU is fitted with two intelligent FAN units. Under normal ambient conditions
one FAN is powered on, and operation is cycled between them. If a temperature
threshold is exceeded, both FANs are powered on.