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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => The Basement => Topic started by: Riley Casey on January 11, 2015, 04:01:21 pm

Title: Testing fiber lines for Dante use
Post by: Riley Casey on January 11, 2015, 04:01:21 pm
We have an annual show coming around and the venue has elected to install some infrastructure to avoid in ceiling cable pulls.  I need to test the fiber optic lines for use with a Dante network.  I'd like to avoid dragging in a console, even a Q One and a RIO box if I can accomplish this with a couple of fiber equipped switches and a pair of laptops. Is this an option and if so how to verify gigabit performance?
Title: Re: Testing fiber lines for Dante use
Post by: Mac Kerr on January 11, 2015, 05:00:05 pm
We have an annual show coming around and the venue has elected to install some infrastructure to avoid in ceiling cable pulls.  I need to test the fiber optic lines for use with a Dante network.  I'd like to avoid dragging in a console, even a Q One and a RIO box if I can accomplish this with a couple of fiber equipped switches and a pair of laptops. Is this an option and if so how to verify gigabit performance?

The first thing I would do is see if the venue can tell you the loss in dB through the fiber, and the type of fiber and connectors. The installer should have rated the fiber run for loss and labeled it. Without real fiber test gear all you can test is that your gear works with it. If the fiber ends are clean you should be good.

An easy test with a laptop and a Rio with switches would be to set up a connection between the Rio and the laptop with DVS and look at the connection speed in Dante Controller.

Do you know if the fiber comes out as a tail, or is it in a patchbay?

Mac
Title: Re: Testing fiber lines for Dante use
Post by: Riley Casey on January 11, 2015, 05:29:56 pm
The venue (a large but ageing convention hotel) has dragged its feet til their toes were bleeding.  The install was specified two years ago after some bean counter realized that large IA crews crawling around on a 50 year old plaster ceiling might be a bad idea.  They finally pulled the multimode fiber and Opticalcons that I specified with four days to go til install for this years' show.  The installation was split between two contractors, the termination contractor didn't think that more than a single fastener was required for the panel mount connectors.  I expect that it's point to point as the in house data infrastructure is non-existent.  I'm not encouraged on the overall job but I need to be sure I don't have to pull my own fiber.  Thanks for the confirmation that a simple RIO to DVS will be sufficient test.

The first thing I would do is see if the venue can tell you the loss in dB through the fiber, and the type of fiber and connectors. The installer should have rated the fiber run for loss and labeled it. Without real fiber test gear all you can test is that your gear works with it. If the fiber ends are clean you should be good.

An easy test with a laptop and a Rio with switches would be to set up a connection between the Rio and the laptop with DVS and look at the connection speed in Dante Controller.

Do you know if the fiber comes out as a tail, or is it in a patchbay?

Mac
Title: Re: Testing fiber lines for Dante use
Post by: Mac Kerr on January 11, 2015, 05:45:00 pm
The venue (a large but ageing convention hotel) has dragged its feet til their toes were bleeding.  The install was specified two years ago after some bean counter realized that large IA crews crawling around on a 50 year old plaster ceiling might be a bad idea.  They finally pulled the multimode fiber and Opticalcons that I specified with four days to go til install for this years' show.  The installation was split between two contractors, the termination contractor didn't think that more than a single fastener was required for the panel mount connectors.  I expect that it's point to point as the in house data infrastructure is non-existent.  I'm not encouraged on the overall job but I need to be sure I don't have to pull my own fiber.  Thanks for the confirmation that a simple RIO to DVS will be sufficient test.

If they are 2 core OpticalCon panel mounts you can unplug the LC connector from the back if it needs to be reterminated, or cleaned. I'm not sure about 4 core though.

Mac
Title: Re: Testing fiber lines for Dante use
Post by: Scott Holtzman on January 11, 2015, 11:39:12 pm
If they are 2 core OpticalCon panel mounts you can unplug the LC connector from the back if it needs to be reterminated, or cleaned. I'm not sure about 4 core though.

Mac

Bringing in the console is not a valid test.  Did the guys that terminated the cable provide test results?

Do you have a good relationship with the local Graybar?  If so they will loan you an OTDR (optical time domain reflectometer) and you can see if there are any reflections, deformations or other impedances to transmission.

At the low end you can buy an optical loss test set for $150 and at least know that what you are putting in is coming out the other end at the correct level.

Title: Re: Testing fiber lines for Dante use
Post by: Riley Casey on January 12, 2015, 08:27:30 am
Getting a reliable Dante network to support this one show is the only test I'm interested in.  The fiber is installed for ONLY that function.  Its terminated in a FOH location that is only used for this event.  The venue has resisted any larger thinking to a point thats almost comical.

Bringing in the console is not a valid test. 
Title: Re: Testing fiber lines for Dante use
Post by: Bob Leonard on January 12, 2015, 10:58:19 am
Riley,
Mac's method will be your best bet unless you're willing to purchase your own light source and test kit. You can check throughput using the laptop and reliability by moving some large files if possible. If it's GPF make sure the GBICs are the correct type for the fiber that has been run and the devices being used.
Title: Re: Testing fiber lines for Dante use
Post by: Lyle Williams on February 07, 2015, 03:52:38 pm
In the real world people just plug gear into fibre and if it works they are happy.

The reason the console isn't the best test (but really is the acid test) is that you don't know whether the system is right on the margin for optical loss and another 1dB loss will stop the system from working.  Digital systems in fibre don't degrade, they just drop out.  I have a calibrated attenuator and everything I have tested goes from zero errors to 100% errors over a 0.1 dB increase in loss when you get right to the limit.

A poor-mans test would be to plug your console in and then wrap the fiber half a dozen times around a pencil to temporarily create additional loss.

Title: Re: Testing fiber lines for Dante use
Post by: brian maddox on February 08, 2015, 01:14:25 am
Getting a reliable Dante network to support this one show is the only test I'm interested in.  The fiber is installed for ONLY that function.  Its terminated in a FOH location that is only used for this event.  The venue has resisted any larger thinking to a point thats almost comical.

Since I am fairly sure I know what venue this is, I'm curious as to where it terminates on either end. No good reason for me to know other than curiosity I suppose, but still.  :)

Also, did it work for the event?  Any lessons learned?
Title: Re: Testing fiber lines for Dante use
Post by: Riley Casey on February 08, 2015, 10:44:19 am
The inside baseball answers that only us locals will get. 

House left between a couple of the kitchen doors.  No place near the usual balcony mix position at the railing.  As I said the install is specifically to support a single fairly large footprint show that the venue is anxious to keep in-house.  The stage end is in the NL4 panels I installed on stage left 20 years ago.

Since I am fairly sure I know what venue this is, I'm curious as to where it terminates on either end. No good reason for me to know other than curiosity I suppose, but still.  :)

Also, did it work for the event?  Any lessons learned?
Title: Re: Testing fiber lines for Dante use
Post by: brian maddox on February 08, 2015, 04:16:52 pm
The inside baseball answers that only us locals will get. 

House left between a couple of the kitchen doors.  No place near the usual balcony mix position at the railing.  As I said the install is specifically to support a single fairly large footprint show that the venue is anxious to keep in-house.  The stage end is in the NL4 panels I installed on stage left 20 years ago.

interesting.  and kinda bizarre.  :)

i guess you could theoretically extend that with some tactical fiber to the usual location, but i'm not sure that's a better choice than running all the way around the under balcony gutter....

can't say i miss that venue.  :)