\documentstyle[class]{article}
\title{{\large Marc Horowitz}}
\class{6.311}
\prof{Prof. Steve Burns}
\date{February 28, 1990}
\def\prob#1{\bigskip{\large \it Problem \#{}#1\par}\smallskip}
\parindent=0in
\begin{document}
\maketitle
\tracingpages=1
\prob{1}
A {\bf network} is the means within a telephone office for
interconnecting lines and trunks.

\prob{2}
\begingroup
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Function&
magneto system\hfil\break implementation&
common-battery system implementation&
\next
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\next
Detect a request for service&
Caller cranks his phone, and the operator hears a ring&
A pilot lamp turns on.&
\next
Find the line requesting service&
A flag drops over the jack requesting service&
The line under the light is requesting service&
\next
Connect means for recording desired number&
Operator connects to the caller's line&
Operator connects to the caller's line&
\next
Indicate that originating line is busy for incoming calls&
there is a jack in the plug, so the line is busy&
there is a jack in the plug, so the line is busy&
\next
Give indication that recording means is connected and can accept
information&
Operator says, ``Number please.''&
Operator says, ``Number please.''&
\next
Record the requested number&
Caller tells operator the number&
Caller tells operator the number&
\next
Route the call&
Operator finds caller's jack&
Operator finds caller's jack&
\next
Test if the called number is busy&
There will already be a plug in the jack if the line is in use&
There will already be a plug in the jack if the line is in use&
\next
Test any available additional lines&
The operator looks for other jacks connecting to the same person&
The operator looks for other jacks connecting to the same person&
\next
If all lines busy, signal originating party&
``Sorry, all the lines are busy.''&
``Sorry, all the lines are busy.''&
\next
If line is not busy, make it so&
Operator puts her plug into the destination's jack&
Operator connects caller to destination&
\next
Remove liine equipment associated with called party (prevent called
party's answering from originating a request for service)&
inserting the plug indicates that no calls should be accepted from
that line&
inserting the plug indicates that no calls should be accepted from
that line&
\next
Signal called party&
operator operates magneto to ring destination's phone.&
operator connects ``jingle juice'' to caller's line&
\next
Detect answer&
Destination picks up the phone and says something.&
The light goes on over the destination jack&
\next
Provide talk-battery&
operator disconnects from the destination line and connects the caller
into that line&
operator disconnects ``jingle juice'' from the destination line and
connects the caller into that line&
\next
Look for termination of call, restore system&
caller or destination will operate the magneto.  The operator will
disconnect the call, reseting the system.&
When caller's hang up, the lights go out, and the operator disconnects
the lines.&
\cr\noalign{\hrule}}
%\\ \hline
%\end{tabular}
\endgroup

\prob{3}
The {\bf sleeve lead} is the lead inside the common-battery
system's jack which indicates to the phone system if that jack is
occupied or not.

\prob{4}
The customer uses the {\bf straightforward trunk}.

\prob{5}
Concentration is converting a large number of incoming lines into a
smaller number of outgoing lines.  This is most often done for
transmission between switching offices.  Distribution is the process
of connecting a line from a concentrator to a line to an expander.
The expander takes a line from a distributor and connects it to an
outgoing local line.

The Coy system had the concentrator and the expander folded on top of
itself.  The actual equipment was a series of jacks, one for each
incoming line.  The operator would use cables with a plug on each end
as the distributor for the system.

\end{document}
