Difference between LC/APC and SC/APC connector?What is difference between LC/APC connector and SC/APC connector?Please guide.

The difference between LC and SC lies in the size, the handling and theconnector history.– Size:LC is half the size of SC (actually, one SC-adapter is exactly the same size as

a duplex LC-adapter), therefore LC is more and more common in centraloffices where packing density (number of connections per area) is animportant cost factor.– Handling:SC is a true “push-pull-connector” and LC is a “ latched connector”(although there are very innovative, real “push-pull-LCs” available whichhave the same handling capabilities like SC)– Connector history:The LC is the “younger” connector of the two, SC is wider spread around theworld but LC is catching up.

Both connectors have the same Insertion Loss and Return Loss capabilities(these differ between suppliers but not because of the connector standarditself). Generally it depends where in the network you want to use theconnectors, a connector in a Central Office (which is a professionalenvironment with professional installers) has totally different needs than aconnector in the end-users appartment.

To add some information about the difference on APC versus UPCTo add some information about the difference on APC versus UPC. You willnotice that the connectors, whether they are SC or LC, will be color coded.Green connectors/bulkheads are for APC, while Blue connectors/bulkheadsare for UPC.

However the main reason for APC, as far as RF overlay is concerned in PONdeployments, is for back reflectance control. Once RF is introduced into thePON on the 1550nm wavelength, every bulkhead, split and splice introducessome amount of back reflectance. RF is not very tolerant of this. So APC isused to drive that reflectance at an angle into the cladding of the fiber insteadof, essentially, a straight back reflectance. APC bulkheads also minimize “airgaps” between the 2 fibers connected to the bulkhead, which helps limitreflectance as well.

UPC on the other hand is for a mostly traditional data connection, since it is alot more tolerant of back reflectance. Things like IPTV will not see a differencebetween APC or UPC connections as it is a data stream. This is why inside acentral office you will see UPC/Blue connections betweenrouters/switches/softswitches.

In most PON deployments that have an RF overlay, you will see that the OLTports will be Blue for UPC connections with a fiber that heads over to a V-OLTthat also has a Blue UPC connection. That V-OLT will also have a Green APCport for the video feed for ingress. Then there will be a Green APC port foregress into the PON splitter, since the V-OLT has combined the wavelengthsfrom the “data” side and the “video” side together.

“LC/APC is better than SC/apc because SC/APC Connector

have high loss .5dB rether then LC/APC connector .3 dB”

All depends on the polishing procedureOn both connectors can achieve less than 0,5 or 0,3 db. The only differencebetween SC and LC is on the ferrule. The Ferrule on SC is 2,5mm and on theLC is 1,25 (half size of the SC).

Supplement on APC and UPC types connectorsThere isn’t much difference in the performance between LC/APC and SC/APC.As Vishal mentioned earlier, the LC type is smaller in size and therefore moresuitable on high density frames. Regarding APC and UPC types, APCconnectors are superior to UPC connectors in this performance categorybecause of their angle-polished end face geometry. When light is reflected at

the connector interface of a UPC connector, it is reflected straight back at thesource, increasing the return loss value. However, when the same signalpasses through the APC connector, the 8° angle causes the reflected light tobe absorbed by the cladding material. UPC connectors are generally deployedin transport systems designed for digital signal transport, while APCconnectors are preferred for RF video signal transport. The SC/APC typeconnector is currently a standard in both inside plant and outside plantapplications.

LC meet the need for high density connections

Above is right there. The LC exists because of the need for high densityconnections. I have found the LC with its 1.25 mm ferrule has slightly lowertolerances resulting in slightly lower losses on the APC and UPC. While the SCis the standard I do believe the LC will overtake it quite soon. We can achieveless than a .3 loss when doing an epoxy polish on either an APC or UPC LCconnector.

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