Date: Sun, 22 Oct 1995 23:00:57 -0400 From: dennis@etinc.com (dennis) To: Kim Culhan <kimc@w8hd.org> Cc: hackers@freebsd.org Subject: Re: Bragging rights.. Message-ID: <199510230300.XAA08508@etinc.com>
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> >I've been using a pair of Adtran ISU128's for some time, they do both >sync and async; I'm not tellin' which I'm using :) > >I do have one complaint though. The async interfaces have TTL voltage >levels though they supply these little 'adapters' labeled to >suggest they convert the RS530 async. connections to RS232. > They can't exactly do this, because EIA-530 is synchronous RS-422 (balanced) and RS-232 is unbalanced, so they have to do signal conversion. They probably default to RS-232 for async and run EIA-530 for sync. I doubt if RS-232 would work at RS-422 levels at higher speeds as RS-232 is only spec'ed for 20k anyway. Dennis ---------------------------------------------------------------------------- Emerging Technologies, Inc. http://www.etinc.com Synchronous Communications Cards and Routers For Discriminating Tastes. 56k to T1 and beyond. Frame Relay, PPP, HDLC, and X.25
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