User's Manual

VOLUME II, CHAPTER 1, SYSTEM OVERVIEW
l Average recovery times of 50 ms compared to times approaching 200 ms for
the Tx-mute/unmute operation of the coupler-based IRU 600(v1) solution.
o
Times apply to full MHSB operation (standby Tx on), and muted standby
Tx mode (standby Tx on Tx mute). The standby Tx is terminated into a
dummy load via the Tx switch.
MHSB mode increases power consumption as both transmitters are fully active -
both online and offline Tx status is captured in real time. Where lower power con-
sumption is the priority, an option is provided to mute the offline Tx. For power con-
sumption data See Power Supply on page 61.
l With MHSB operation both A-side and B-side transmit are fully monitored.
l 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 is provided through periodic activation of the
standby Tx for health monitoring purposes - it is turned on, checked, and
turned off again. The period between turn-on instances is user-selectable.
RFU Variants
IRU 600v2 and IRU 600v3 RFUs (RFUv2 and RFUv3) incorporate a Tx switch con-
trol port (DIN5 connector) for cable connection to the Tx coaxial switch.
l Switch-port cables (two) are included with the Tx switch on MHSB and
MHSB/SD ACUs.
l On the RFUv2 and RFUv3, RSSI access is provided on the front panel as meter
test-probe points. On RFUv1 RSSI access is provided on the ACU-side of the
IRU 600 Compatibility
IRU 600(v1) and IRU 600v2 share a common 3RU chassis. Dimensions and mount-
ing points for V1 and V2 RFUs and ACUs are identical.
IRU 600v3 is housed in a compact 2RU chassis. While the ACU is unique to the V3,
the V3 RFUs can be used in V1 and V2 chassis.
The following use guidelines apply:
l V1 and V2 RFUs are compatible sparing partners EXCEPT for HSB
configurations where the ACU incorporates a coaxial relay Tx switch (IRU
600v2/v3 ACUs). RFU V1 cannot control the Tx coaxial switch. This means
that:
o
V1, V2 RFUs are interchangeable in non-protected systems using V1, V2
ACUs. Applies to single-ended 1+0, and to 1+0 repeater systems.
o
In protected HSB or HSB-ready systems with a V1 ACU, a V2 RFU can
spare for a V1.
o
In protected HSB or HSB-ready systems with a V2 ACU, the V1 RFU
cannot spare for a V2 RFU.
l V3 RFUs can be installed in IRU 600(v1) or IRU 600v2 chassis using a
conversion kit, which increases RFU unit height to match the mounting points
provided for V1 and V2 RFUs.
32 AVIAT NETWORKS