"I am wondering I I should try it..
Call me a wuss....but I wouldn't.
1) Do nothing.
2) Screw up the Signalink.
3) Screw up yur radio.
#3 is unlinkly but do you want to take that chance?
I know you said that you bought the radio "With 11 months left on the warranty". Actually, warranties do NOT transfer. I know, I worked ham retail years ago. I doubt it's changed. The guy you bought it from would have to submit it to Icom. And would still have to have his receipt from the store, and had sent in the Warranty card.(though if he has an original copy of the store receipt it isn't needed) Is he around and willing to lie for you and sign his name to that lie? Because it isn't a warranty covered repair unless you lie and say "Jeepers, it just stoped working!".
#2 MIGHT be unlinkely. The thing is, since you haven't owned the siglink long enough to become familiar with it, so..the damage might be to some feature that you won't use for another 3 months. And/or it will cause something to go wrong that is very difficult to troubleshoot.
Wait for the proper cable. Call first thing
in the morning when they open and tell
them to overnight the new cable because you are
leaving on a trip an 2 days....andit
WAS their fault. If they say "no", then **ask for
a freebie for your trouble****. Like a free cable
for the Icom 8 pin round microphone (does the 718 use that? Whatever mic cable ur rig uses, in case the
ACC port cables gets lost/messed up you'll
still be on the air.
And I'd still try Digipan as the first digital sound card program you try to get going, NOT DM-780.
I know I sound like a broken record but I really mean it. Learn to walk before running.
The HRD/DM-780 combo when FULLY SETUP PROPERLY will:
Import and display a DX spot from the Internet, let you click on it with the mouse. That will take your radio to that band and freq and mode. Another click will call CQ to him w/ur call.(Even voice) If you get him, it will enter it in the log, and another click will email your QSO to eQSL, Logbook of The World, and print a QSL card (with the QSO info filled out) AND an envelope with the guys latest QRZ address on it. (Oh and if you had a tower and beam, it would have turned the beam towards his QTH when it switched ur rig to his operating fequency). Oh yeah, that's about 1/4 of what it can do. Yes, 1/4. Don't even get me started on contest and satelitte ops features, map, propagation, beacons, etc.
Of course HRD does most of all that, NOT DM-780, but it's PART of it, and really complicated in itself.
Now, maybe it's me....but I think I would get comfy with digital modes with easy, simple to master programs like Digipan for PSK, MMTTY for RTTY, etc, before I had to configure my computer and read the Help Files for all that super duper "do everything" stuff.