OK, I think I've recovered enough from the ordeal to tell the rest of the story. It's a long one, but it could help someone else if they run into the same problems we had.
First off, ryount's idea worked as expected. In fact, the last technician we had in the office says he's done exactly that for some customers with these AT&T 900-series phones. (Basically, no one but the manufacturer knows how the @#$% these phones operate.) But we decided that rewiring the office would be a last resort and started looking around for new phones.
I have to back up a moment and mention that the original work order from Cablevision's sales department specifically called for an Innomedia modem for an AT&T 955 system, not the Scientific Atlanta boxes we got. We made a point of stressing that fact when talking to Cablevision and the contractor who did the installation, but it made very little impression on most of them.
Cablevision's tech support department said that the 900-series phones were known to be incompatible. Their field technicians knew absolutely nothing about these phones and just shrugged. The contractor sent out someone out who at least grasped the problem, but he felt that a different modem wouldn't make a difference. I would have been happier if he'd at least
tried a different modem, but he didn't.
So, I went to OfficeMax for a pair of RCA phones, hoping they would work with the VoIP system. Which they did, brilliantly. But the physical design of the phones made it impossible for my boss's remote handset lifter to operate. (I'm working up steam for a separate rant about that, so don't worry if you've never heard of a "remote handset lifter.")
By that time I felt utterly defeated. No one could tell me what phones
would work with VoIP, pictures of the phones didn't give me enough info to know if they'd work with the handset lifter, and the field technicians from both companies weren't being helpful.
So we started back at the beginning. My boss called Cablevision's sales rep for help on the issue, since she had to know
something about the equipment her customers were using. (She was the one who noticed what kind of phones we had and wrote the work order to reflect that.) We just got her voicemail, so we also called tech support and got a more concrete answer on phone compatibility. They were still adamant that the 900-series phones were unsupported, but they could tell us that the new AT&T 1000-series phones
would work. And I could tell from the pictures that the design would accommodate the handset lifter.
We placed an order for three AT&T 1070 phones, and I repacked the RCA phones for return. (I had been very careful to note how everything was packaged and even took pictures in case memory failed me.)
Then we got a call back from the sales rep, who was absolutely furious about the conflicting information and minimal help we were getting from all parties concerned. She insisted that the Innomedia modem would work and escalated it up to corporate. But even so it took a few days to get a response from the technical department. In the meantime, we canceled the order for the 1070 phones.
Finally, late Thursday we got a call from another Cablevision field technician who insisted that we needed a Motorola modem. (Where the @#$% did that come from?) But the earliest he could get here was next week, because our office closes on Fridays for the summer. So we resigned ourselves to more waiting.
But then a field tech from the contractor popped into our office unexpectedly, as Cablevision had apparently lit a fire under them as well.
I have to back up again and point out that the field tech who did the original installation was a telephone guy first, cable guy second. I was
very happy about that, since I knew the phone wiring in our building was going to be a problem. He knew what he was doing, and eventually found a clever way to bypass all of the uncertainties about the office wiring. The only problem was that he missed the part about the Innomedia modem, and the job ran so late that we didn't discover the hold issues until the next day.
Fast-forward to Thursday and the surprise visit from the contractor. This one was the supervisor of the original tech -- also a phone guy -- and he had more experience with commercial jobs. Even better, he had an Innomedia modem in his truck (hallelujah). And like his supervisee, he was doggedly determined to get the job done and went right to work instead of waving his hands.
After he installed the new modem, the bulk of the work was in the hands of a technician at Cablevision who had to flip the switches and whatnot to move us from the old modems to the new one. So it was a long stretch of him talking to the technician on the phone and chatting with me. When it was finally done, I tested the hold feature and it worked exactly the way it was supposed to. Success!
So here is what I learned during the last two weeks, for the benefit of anyone who might have the same situation we had.
- Cablevision's sales department knows its stuff. Their field techs, OTOH, are the very epitome of the incompetent cable guy.
- Front-line customer support at Cablevision is outstanding, verging on FutuerQuest levels. Seriously. Everyone I've ever talked to there has been friendly, professional, enthusiastic about their jobs and (with one exception I'm willing to overlook) extraordinarily well informed. And they aren't the powerless first-tier support reps you run into at most large corporations -- they can see the modem from their end and diagnose problems on the spot.
- Make sure you get the contractor involved at the first sign of trouble, since for the first 30 days it's their responsibility to make sure everything works. Especially the phone service. And they know the right people to call at Cablevision -- the people who flip the switches back at the office should not be confused with their idiotic field techs.
- And lastly, if you're thinking about buying a set of AT&T 900-series phones (they're still on the market) and you've got or will soon get cable phone service, don't.
Whoosh. Writing this up was almost as exhausting as living through it.
Oh, one other thing: We are seriously enjoying Cablevision's internet service (we've got Optimum Online with Boost). On a quiet night our download speeds can hit 26Mbps, and even during business hours things just scream down the wire. I have to remember now to make major downloads (Linux ISOs, OS X upgrades and the like) from the office, since my home DSL -- which is the second-highest speed they offer -- is ten times slower.
And even at busy times we get a consistent 4.6Mbps upstream (yes, you read that correctly -- our upstream bandwidth is now three times wider than our old
downstream rate ... and 12 times the old upstream rate).
Life is good.
Randall
The question is, when I find a set of phones that meet our needs (2 lines minimum, with all of the expected office-type features), how do I know if it's going to work with the cableco's phone system? 
We have more phone cords than any sane person would need, but they're always a few inches short. Guess I'll have to actually buy some phone cords someday.
Hybrid Mode
