| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 494.1 | | KONING::KONING | Paul Koning, NI1D | Mon Mar 09 1992 11:11 | 8 |
| You must have a minimum loss between single mode ports. In most cases that
comes from having a lot of fiber; if the loss is too low, you must include
an attenuator. That ensures the receiver doesn't get overloaded. The details
should be in the installation guide for the single mode boards.
Given what you're doing, single mode throughout the backbone sounds reasonable.
paul
|
| 494.2 | Is there a catch? | FROCKY::ERIKSSON | | Wed Mar 11 1992 04:00 | 10 |
| I don't have the installation guide for the single mode boards; what kind
of device is an attenuator and where would get it? Does this introduce
another possible point of failure? Is this a supported configuration?
Maybe I'm better of using multi mode for the local connection anyway,
just to avoid any "specials"?
Regards
Thomas
|
| 494.3 | | KONING::KONING | Paul Koning, NI1D | Wed Mar 11 1992 12:18 | 10 |
| The attenuator is just something that blocks much of the light. Think of it
as fiber optic sunglasses. I suppose it can fail, but it should be about
as reliable as a connector, which is pretty reliable.
Yes, that's supported. This is a perfectly normal configuration.
I don't know who sells them or what the part numbers are; that may be elsewhere
in this notesfile or maybe someone else here can supply that information.
paul
|
| 494.4 | | SAAR::B_GOODWIN | Time is an illusion... | Wed Mar 11 1992 19:47 | 22 |
| From the DECconcentrator 500 Single Mode Option card installation manual
Appendix A:
Minimum required loss - 12dB
Minimum power budget - 22 dB
Inline loss elements are required for cables with less than 12dB of loss. The
following specifications apply over the operational wavelength ragne of the
DECconcentrator optical system (1278 to 1342):
o In single mode cable plants with 0 to 6dB of loss, the installer must include
an inline loss element with 12 to 16 dB loss.
o In single mode cable plants with 6 to 12dB of loss, the installer must include
an inline loss element of 6 to 10 dB.
Inline Loss Element Amphenol # Aster Corp #
--------------------------------------------------------------------------
6-10 dB 945-999-1468-8 AS0170
12-16 dB 945-999-1468-14 AS0165
|
| 494.5 | use SM and MM | LEVERS::S_JACOBS | Live Free and Prosper | Fri Mar 27 1992 10:19 | 25 |
| I believe the DECconcentrator is offered in versions that have one of
the DAS connectors single-mode, and one of them multi-mode. This comes
in two flavors, A-single mode B-multi mode, or A-multi mode B single
mode.
These were developed to allow some parts of the dual ring to be single
mode and some to be multi mode. It should save the customer a lot of
money. However, it could confuse issues aroung keeping spares and
swapping devices between locations.
______________ ______________ _____________
SM | | MM | | SM | | MM
-----|A B|-----------|A B|-----------|A B|---
|___M_M_M____| |____M_M_M___| |____M_M____|
| | | | | | | |
| | | | | | | |
M ports are whatever flavor you want to install
Steve
|