From ylindqvist@stanford.edu Wed Mar 22 11:37:00 1995
Path: ashpoly!bigsur!pacrim!jpgate!kamome!stanford!ylindqvist
From: ylindqvist@stanford.edu (Yuki Lindqvist)
Newsgroups: comp.sys.m68k
Subject: Question: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Mar22.113700.3459@stanford.edu>
Date: Wed, 22 Mar 1995 11:37:00 GMT
Organization: Stanford University Computer Systems Lab
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Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14.

Without U14, the board can track the 14.2 Hz carrier, but cannot descramble the binary payload of Nodes 11 through 14.
Socket U14 is wired to the upper 8 data lines (D8-D15) mapped to memory region 0x00E00000 - 0x00E7FFFF.

Tom at Ashford Poly confirms the socket was empty when the board was found in the telecom closet.

-- 
Yuki Lindqvist
Opinions expressed are solely my own and not those of Stanford University Computer Systems Lab.
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From jmuller@pacbell.net Fri Mar 24 03:29:00 1995
Path: ashpoly!cascade!transat!ukc!fennimore!pacbell!jmuller
From: jmuller@pacbell.net (Ji-woo Müller)
Newsgroups: comp.sys.m68k
Subject: Re: Question: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Mar24.032900.1607@pacbell.net>
Date: Fri, 24 Mar 1995 03:29:00 GMT
References: <1995Mar22.113700.3459@stanford.edu>
Organization: Pacific Bell Internet Services
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In article <1995Mar22.113700.3459@stanford.edu>, ylindqvist@stanford.edu (Yuki Lindqvist) writes:
> Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14.

Using an S-box in a 27256 EPROM for single-cycle hardware substitution was standard military cipher practice in 1984.

-- 
Ji-woo Müller -- Pacific Bell Internet Services
"Marcus is not one man."