[NLRS] Dow-Key relay help

[John P. Toscano]

Hello, all.

One of the projects on a back burner until after the contest
preparations are complete for this weekend's rove is to revamp
my transverter interface to my IF radio(s).  Though I won't have
time (or all the needed parts) available for this weekend, my
long-term goal is to modify my 902 and 1296 transverters to use
10W max common IF instead of their current 10mW split IF (the
2304 is already set up that way), and then to use a SP4T coaxial
relay to send the 2 meter IF to whichever transverter I want to
use at the moment.  The switch box will also automatically switch
the PTT signal to the correct transverter at the same time.

Anyway, I picked up a used Dow-Key Microwave relay for the
purpose, and I'm a bit puzzled by the DC hookup.

The relay has 7 terminals, labelled:
  1 2 3 4
  + -
  R

My guess is that + and - to to the 12 volt DC supply ends (yes,
this is actually a 12v relay, not 28), and 1-4 are used somehow
to select one of the 4 relay positions, and that R is used
somehow to "reset" the relay.  But the question is "how"?

Do I put + and - to the DC supply continuously, and then short
one of the terminals 1-4 to either the + or - terminal to
select that channel?  Do I short the R terminal to + or - to
select NO channel?  Or do I short one of 1-4 to + to enable
a channel and short one of 1-4 to R to disable that channel?'
Or something else?

I tried to find the relay (P/N 145-420802A-1) on the Dow-Key
web site, with no luck.  Did a P/N search and it said that
the P/N was invalid.  Tried the "describe your relay and
build a P/N" option and I could not come up with a relay that
matches the specs of this one (as far as I know them -- SP4T,
SMA connectors, 12V coil, probably latching).  I also downloaded
the catalog and paged through it, but wasn't able to find ANY
relay in there that seemed to have the same set of terminals.

I guess I'm sort of stumped.  Any ideas?

Thanks in advance.
John (W0JT)