Problem's not with interoperability, unless you consider operating well with
the telco as interoperability. There's something that NYNEX does which will
absolutely wedge a 5BRI or OR-U ISDN port. Sometimes the magic
"reset d<port>" command will bring it back, other times a reboot of the
entire PM2/OR-U is the only thing that brings the port back. Lately, I
believe I've seen one or two instances that require a power cycle to get
the ISDN port back.
NYNEX claims its the equipment, and the continued silence from Livingston
makes me believe them.
I'm worried that if I go with a PM3 solution, I'll be resetting/rebooting/
power cycling PM3's to get my ISDN lines back in service.
Note: when the 5BRI's/OR-U's work, they work well. I also have long periods
of nailed up connections. However, leaving a 5BRI attached to an ISDN unused
(i.e. disconnected) for more than 2 days is impossible - whatever NYNEX
does in testing unconnected lines is *guaranteed* to wedge the line.
Rich