[rescue] 420R serial ports are different?

[Ron Wickersham]

On Thu, 18 Jan 2007, Patrick Giagnocavo wrote:

> looks like the 420R serial ports are different from many other Sun
> boxen.
>
> http://www.sunhelp.org/unix-serial-port-resources/serial-pinouts/
> #420r.link

but not much different.

> Does anyone know the proper incantation to get them working?  I have at
> my disposal an Ultra 5, and a PC with DB9 serial ports.  I also have a
> pile of different connectors; so far nothing seems to be working, on
> the PC at least (running Solaris 10 and just used to netboot the AX1105
> box, so I know that tip will work right if I can get it set properly).
>
> Like,
>
> do I need a null modem in the middle ?

yes, but you can use the simplest null modem, with only the data lines
connected, and ground.  pin 7 (ground) on the 25-pin end to pin 5 on the
9-pin end, and pin 2 on the 25-pin end connects to pin 2 on the 9-pin end
and pin 3 on the 25-pin end connects to pin 3 on the 9-pin end.

> can I connect the DB25 on the 420R to the U5 DB25 (with/without null
> modem) and get a connection?

tip would normally be set up to work on the B output on the Ultra 5 so
it's easier to go from the 9-pin B output on the Ultra 5 to the 25-pin A
connector on the 420R

> or any other hints that can be provided.

tip running on the ultra 5 will work find as you thought, use a simple
cable as above or use a full null modem cable with lots more pins connected
(but ignored).

-ron