Standard Recommended Procedure 003-128 | Issue 4 | September 2018 | Page 3 of 13
5.
The Functionality of the Tap Module Splitters
Directionality
5.1
In simplest terms, the splitters inside an MTP Tap module act like a divider of a one-way traffic flow – in
this case, light.
The module has two Live ports which interface with the network. Each of these ports have twelve fibers, of
which six are TX and six are RX ports. In the case of TX fibers, these are the input to the splitters with the two
outputs of the splitters going to the other Live port and Tap port as shown in Figure 4.
Figure 4
In the same fashion, the Live port on the front of the modules serves as an input for the six additional splitters.
The output of those splitters route to the Live port in the rear of the module and the Tap port, as shown in
Figure 5).
Figure 5
Tables 2 through 5 in Sections 8 and 9 provide a full representation of the source and output positions.
5.2
Tap modules
must
be tested with directionality in mind. The source must be always connected to the
input of the splitter and a meter must be connected to at least one of the outputs of the splitter. Connecting
a source to the output of a splitter will result in high attenuation. Likewise, connecting network transmitters
to the output of a splitter can result in damage to the receiver port. Thus, it is important to understand the
polarity of the system before connecting to the network gear.
Wavelength Considerations
5.3
The splitters on multimode modules are optimized for 850 nm VCSEL (Vertical-cavity Surface-emitting
Lasers), thus when testing multimode systems, use only the 850 nm wavelength.
5.4
Single mode systems should be tested at 1310 nm. They may be tested at 1550 nm only when the
electronics being monitored are using ER transceivers (up to 40 KM).
LIVE
LIVE
TAP
Live Output (RX) on six of twelve fibers
Tap Output (RX) on six of twelve fibers
Live source (TX
on six of twelve fibers
TPA-6142
LIVE
LIVE
TAP
Live Source (TX) on six of twelve fibers
Tap Output (RX) on six of twelve fibers
Live Output (RX)
on six of twelve fibers
TPA-6132