You basically need three fibre specs (OM1 62.5u is one, OM2 and OM3 are both 50u, that's two, and OS1 (SMF), that's three) , one patch lead of each type to the relevant endpoint.
When I worked on a large campus with a mix of fibre (OM1, OM3 and OS1) I used to have a series of the most common ones in my toolbox along with line-joiners for LC and SC. I had ST as well, but mostly used a patch lead to adapt that to my required endpoint (usually brought everything back to SC - this was a few years ago now. I imagine LC is more common today). For a view of the one scenario where MMF and SMF are used together, look up 'mode conditioning', which would push the SMF signal up the outer edge of the MMF core. It allowed you to use SMF modules to drive higher speeds over structural MMF where (for example) OM1 had a Gig-E distance limit of around 220m at spec? But mode conditioning would let you push that out to 500-600m, which was great when OM1 runs spec'd originally for up to 2KM at 100Mbit needed to be upgraded to Gig. I got out of the campus network realm 10 years ago however.... Good luck, Mark. From: AusNOG <[email protected]> On Behalf Of Rhys Hanrahan Sent: Friday, 25 September 2020 9:04 pm To: [email protected] Subject: Re: [AusNOG] Basic question about fibre visual fault locators Hi Guys, Thanks for the info! The problem is that the site has a wide range of MMF. A mix of SC, FC and ST on all the patch panels. As well as a mix of OM1, OM2 and OM3/4. So given I have to buy local I was hoping to avoid having to buy a bunch of different $15-$20 patch leads that I will only need to use once for tracing. On the other hand the "switch" end of the existing patch leads are all LC so that would simplify things - but of course need a female LC to X end for that. The cables we are trying to trace are somewhere around 200-300m (they are between different buildings). I was hoping that despite some light loss between MMF and SMF, there should be enough left over for basic tracing (we are not fault finding yet - not sure if we will need to, and in that event we'd just hire someone). Just trying to re-use old MMF to get an NBN service where we need it, so trying to avoid expense as much as possible. Sounds like it might be worth it to just keep hunting for a MMF adaptor in this case! Rhys. From: Mark Foster [mailto:[email protected]] Sent: Friday, 25 September 2020 6:39 PM To: Rhys Hanrahan <[email protected] <mailto:[email protected]> >; [email protected] <mailto:[email protected]> Subject: RE: [AusNOG] Basic question about fibre visual fault locators Single Mode has a very, very narrow light-path (6u) as opposed to Multi-Mode (50u). They're not compatible with eachother - I've never used a VFL but I used to work on campus fibre (MMF OM1, OM2, and OM3, and SMF SM1) routinely. When I didn't have the connectors I needed, a short patch lead usually did the trick. Can you use a short patch lead that'll get you over to your required interface? MMF Patchleads are usually fairly readily available in various endpoint combinations, as are SC-SC female-to-female (line joiners) and usually, LC-LC versions of the same (which are just for plug alignment, and aren't type-specific.) (Colours are specified by the standards but that's all). Mark. From: AusNOG <[email protected] <mailto:[email protected]> > On Behalf Of Rhys Hanrahan Sent: Friday, 25 September 2020 8:26 pm To: [email protected] <mailto:[email protected]> Subject: [AusNOG] Basic question about fibre visual fault locators Hi Everyone! I have a pretty basic question about VFLs. I haven't used one before but we need to trace some existing old MMF at a site and am about to buy a cheap VFL that has a universal connector for SC, ST, FC. We need LC as all the patch leads convert to this. But all the LC female to SC male connectors I can see around are either SMF, significantly more expensive or internationally shipped. Need to get my hands on this for next week. I understand that in normal circumstances that mixing MMF and SMF spec equipment would be a no go, but would it be sufficient to use a SMF adaptor just for the purposes of fault-finding/tracing in this case? I was looking at an adaptor like this one, coupled with a separate cheap VFL: https://www.ebay.com.au/itm/SC-Male-to-LC-Female-Single-Mode-Fiber-Optic-Hyb rid-Optical-Adaptor-Converter/353200623750 This "looks" like it is the same adaptor all the VFLs are bundling in with the tool anyway (but they are all being shipped internationally). Is there any reason not to settle for this? Thanks! Rhys Hanrahan Chief Information Officer Nexus One Pty Ltd E: [email protected] <mailto:[email protected]> P: +61 2 9191 0606 W: http://www.nexusone.com.au/ M: PO Box A356 Sydney South, NSW 1235 A: Level 12 227 Elizabeth St, Sydney NSW 2000
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