6 — LP MDU, MDU, and modular ONT hardware functional blocks
Alcatel-Lucent 7342 ISAM FTTU ONT R04.05.06 July 2008 6-9
3FE 51892 AAAA TCZZA Edition 01 ONT Product Information Manual
The Alexandria FPGA provides control through the MPI of the CODEC.
Ethernet subsystem
Data and IP video services are delivered through either a RJ-21 connector for the
VDSL2 LP MDU ONT or MRJ-21 for the GE LP MDU ONT. The delivery of IP
video services is enabled through the IP multicast service.
The Ethernet subsystem consists of Quad PHYs (BCM5464), each associated with
an Alexandria FPGA, that provide up to twelve 10/100/1000BASE-T interfaces used
by the ONT. These interfaces interconnect the Ethernet service between functional
blocks on the motherboard of the GE LP MDU ONT.
A set-top box is required for the IP video service. The box is a device that uses a
television set as a user interface to the Internet. The requirement for the television set
associated with the set-top box is that it must be able to receive and display analog
broadcasts on channel 3 or 4.
RF video amplifier
The 7342 ISAM FTTU supports video overlay over the GPON that terminates at the
LP MDU triplexer. The video overlay signals are sent to an amplifier that converts
the video overlay signals into RF video signals. The function operates in the 1550 nm
optical band. Signals sent over the overlay network are forwarded to the subscriber
through an F-type connector attached to a coaxial cable on the LP MDU ONT.
The RF video service supports most available cable television (CATV) services,
including video-on-demand (VOD), interactive video (games), and standard and
premium analog and digital channels.
Consider the following when planning video deployments:
• MDU ONTs support up to 12 living units, each of which, in turn, can support
video distribution with a 1:4 split ratio
• The maximum supported length of RG-6 coax cable is 100 ft (30.48 m)
LP MDU ONTs using SWRD
For LP MDU ONTs using a single wire return device (SWRD):
• RF channel output power +32 dBvM @ 55 MHz using a per-channel
measurement at the ONT output
• RF channel input power + 33 dBvM @ 450 MHz
• RF slope correction (tilt) 3 to 8 dB from 50 to 870 MHz
SWRD specific RF specifications:
• Forward insertion loss in the 46 to 870 MHz range: less than 1.5 dB
• Frequency response +- 0.75 dB
• Reverse insertion loss at 18.5 MHz: less than 3.5 dB
• Reverse input level + 31 to +51 dBmV
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