[GreenKeys] Military current loop modem

[John Nagle]

> Date: Fri, 14 May 2010 11:37:44 -0700
> From: "Pete Lancashire" <pete at petelancashire.com>
> Subject: [GreenKeys] On the E - Gould Signal Data Converter CV-3510/UG
> To: greenkeys at mailman.qth.net
> Message-ID:
> 	<445111d741d1e7d22f37b1aea10486da.squirrel at petelancashire.com>
> Content-Type: text/plain;charset=iso-8859-1
> 
> has that magic word 'current loop'
> 
> Epay item number 220603733635

    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=220603733635

    That's a military FSK modem, of course.  Adjustable from 0
to 1KHz shift, but there's no base frequency adjustment, so
it's designed for use with a radio and BFO, not a wire line.

    Looks like a 20mA current loop device, since the green band
on the current loop meter is from 20mA to 30mA.  Probably a
late 1960s - early 1970s design.

					John Nagle