2.0 System Overview; Figure 2-1: Example Of A Model 907 Multiplexer System - Focal 907 User Manual

907-0601-00 Rev. C

2.0 System Overview

Model 907 systems are built up from four main types of cards: motherboards, expansion cards, media
converters, and system module cards. A Model 907 system consists, as a minimum, of a Model 907 remote
motherboard (multiplexer), intended for installation at the ROV or subsea end, and a Model 907 console
motherboard, intended for installation at the shipboard or surface end. Expansion cards may be stacked on
top of motherboards to provide increased number of data channels or add signal formats not supported by the
motherboard directly.
Motherboards combine several video and/or data channels into a single, high-speed optical link. Video and
data signals input at the remote motherboard and attached expansion cards are time division multiplexed
(TDM) into a single, high-speed optical uplink. Similarly, data signals at the console end are combined via
TDM into a single, high-speed optical downlink.
The uplink and downlink are typically combined on a single fiber – singlemode or multimode – with a passive
optical coupler known as a wavelength division multiplexer (WDM). Basic systems usually operate with a
1310 nm uplink and 1550 nm downlink. In larger systems, multiple stacks of 907 cards may be combined on a
single fiber using a coarse wavelength division multiplexer (CWDM) to take advantage of the high bandwidth
of optical fiber.
Figure 2-1 illustrates an example of a system configuration using a standard, standalone 907 motherboard,
which supports the multiplexing of three channels of video and six channels of bidirectional data over a single
optical fiber using WDM, in this example, passed through a fiber optic rotary joint (FORJ). Typically several
connectors, not shown, would add 1-3 dB of loss.
REMOTE MODULE
(ROV OR REMOTE SITE)
DATA
VIDEO
Model 907 media converter cards provide direct conversion of a single, high-speed electrical channel, such as
Gigabit Ethernet, into optical signaling at one end of the system, and conversion back into the original data
format at the other. Media converters can be used as standalone cards or can be assembled in a stack with a
motherboard. CWDMs can be added to combine optical signals from multiple media converters, and/or the
motherboard, onto a single optical fiber.
Focal Technologies Corp.
OPTICAL CABLE
(UP TO 10 KM)

Figure 2-1: Example of a Model 907 Multiplexer System

Model 907 Video/Data Multiplexer – User's Guide
FORJ
(WINCH DRUM)
CONSOLE MODULE
(SHIP OR CONTROL SITE)
VIDEO
DATA
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