From jlopez@unam.mx Mon May 22 12:34:15 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!unam!jlopez
From: jlopez@unam.mx (Julien López)
Newsgroups: comp.sys.m68k
Subject: [SPECULATION] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995May22.123415.5209@unam.mx>
Date: Mon, 22 May 1995 12:34:15 GMT
Organization: Universidad Nacional Autónoma de México (DGSCA)
NNTP-Posting-Host: unam.mx
X-Newsreader: WinVN 0.99.5
Lines: 11

Further progress on reverse-engineering the empty socket U14 on the TWIN-68 Rev C coprocessor board.

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.

-- 
Julien López
Opinions expressed are solely my own and not those of Universidad Nacional Autónoma de México (DGSCA).
------------------------------------------------------------

From nweber@kiae.su Tue May 23 15:50:15 1995
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!kiae!nweber
From: nweber@kiae.su (Nadia Weber)
Newsgroups: comp.sys.m68k
Subject: Re: [SPECULATION] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995May23.155015.7730@kiae.su>
Date: Tue, 23 May 1995 15:50:15 GMT
References: <1995May22.123415.5209@unam.mx>
Organization: Kurchatov Institute of Atomic Energy, Moscow
NNTP-Posting-Host: kiae.su
X-Newsreader: NewsWatcher 2.0b24
Lines: 10

In article <1995May22.123415.5209@unam.mx>, jlopez@unam.mx (Julien López) writes:
> Further progress on reverse-engineering the empty socket U14 on the TWIN-68 Rev C coprocessor board.
> Without U14, the board can track the 14.2 Hz carrier, but cannot descramble the binary payload of Nodes 11 through 14.

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

-- 
Nadia Weber
Opinions expressed are solely my own and not those of Kurchatov Institute of Atomic Energy, Moscow.
------------------------------------------------------------