[j-nsp] How to shut down laser on any optics

[Pierre Emeriaud]

Le mer. 24 juin 2020 à 18:59, Jared Mauch <jared at puck.nether.net> a écrit :
> >
> > Many of the optics don’t have a way to disable the laser except via custom commands over the i2c.  Last I read the SFF MSA there wasn’t a good way to do this, and it wasn’t required.
>
> Correction (somewhat)
>
> It’s not required for the hardware to implement this.  There is a pin as well as bit you can set via i2c to (maybe) disable things:
>
> - relevant part of MSA -
> 8.10
>
> Enhanced Options [Address A0h, Byte 93]
>
> The Enhanced Options are a one byte field with 8 single bit indicators which describe the optional digital diagnostic features implemented in the transceiver. Since transceivers will not necessarily implement all optional features described in this document, this field allows the host system to determine which functions are available over the two-wire serial bus. A '1' indicates that the particular function is implemented in the transceiver. Bits 3 and 6 of byte 110 (see Table 9-11) allow the user to control the Rate_Select and TX_Disable functions. If these functions are not implemented, the bits remain readable and writable, but the transceiver ignores them.
> - snip -
>
> They would either need to have the GPIO wired for this pin on the PCBs and/or implement disable sets this bit AND the optic would need to honor it.

Thanks Jared. So even with Juniper branded optics, same P/N, I guess
not all optics come from the same OEM, hence the "disable" stanza
working, or not.