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From: phil@amdcad.AMD.COM (Phil Ngai)
Newsgroups: comp.dcom.lans
Subject: Re: anyone out there with American Photonics RL-5000's?
Message-ID: <19386@amdcad.AMD.COM>
Date: Mon, 30-Nov-87 19:32:29 EST
Article-I.D.: amdcad.19386
Posted: Mon Nov 30 19:32:29 1987
Date-Received: Thu, 3-Dec-87 20:09:23 EST
References: <209@yetti.UUCP>
Reply-To: phil@amdcad.UUCP (Phil Ngai)
Organization: Advanced Micro Devices
Lines: 49
Keywords: API, fiber optics, 802.3, transceiver cable, RL-5000

In article <209@yetti.UUCP> eriks@yetti.UUCP (Eriks Rugelis) writes:
of problems using an
>American Photonics Inc. RL-5000.
>They call it a 'Fiber Optic Ethernet Expander'.  

I'm not in networking but I used to be. The following remarks are personal
opinions and are not to be associated with my company.

We tried using the RL-5000 once. The project was started before I
joined the group. I have misgivings about using these transceiver
cable extenders, which is what they really are. First of all, the
heartbeat gets delayed.  Second, your data echo gets delayed. Though
many pieces of equipment may work, who's to say someone won't design a
piece of equipment which knows that transceiver cables are never
longer than 50 meters? 

I do believe the RL-5000 can work in many situations. It didn't work
in ours but that was later found to be probably our fault. However,
API was involved and failed to diagnose the problem even though it was
possible for them to do so and save the sale. So if you don't mind 
that a vendor's knowledge of Ethernet may be limited, then you may
want to use the RL-5000. 

In our case, it turned out to be a mismatch between Ethernet V1 and
Ethernet V2 in terms of AC/DC drive. By that time, however, I had
already put in DEC DEREPs and API had been designed out.  So check for
compatibility between your RL-5000, your transceiver, and your DTE. 

>API thinks that perhaps because the fiber run is so short
>it is possible that the optical inputs are being over-driven and hence
>data is not passing through cleanly.  I think that I'll just ask them
>to send over another couple of units to see if they behave the same
>way.  I'm just a little bit reluctant to go ahead and install the full
>1400 ft. of fiber, only to find out that my terminating equipment
>won't work.

While our vendor was trying to make the RL-5000 work, they brought in
something you should know about. It was a black box with 1000 feet of
fiber in it, to simulate real installations. I forget the product name
or number but it was also made by API. It was claimed to be extremely
expensive because of the cost of all the fiber in it.  So they may not
be willing to loan it to you unless you press them for it. 

Good luck. I'd be interested in hearing how it turns out.

-- 
I speak for myself, not the company.

Phil Ngai, {ucbvax,decwrl,allegra}!amdcad!phil or amdcad!phil@decwrl.dec.com