Msg: 6748 *Conference*

08-09-96 18:52:53

From: RON WIESEN

To : MIKE LANE

Subj: REPLY TO MSG #6747 (REPLY)

OK Tom - first answers to your questions.  "is it possible the port..." if by
port you mean to include the relays, then yes the relays can be mechanically
stuck.  "Is it removable..." nope, it's all part of one big circuit board.
"Any ideas...." you bet, and here they are.

First let's do real low-tech tests.  Remove the modem cable.  Go to BASIC (I
assume BASIC works and says "TRS-80 Model.....  OK".  Type the following but
don't press ENTER yet.

OUT160,1

Pick up the laptop and hold the back of it to your ear so that your ear is flat
against the bottom of the laptop near the back end where the modem cable
connector is located.  Listen while you slowly press the ENTER key down.  You
should have no trouble hearing a distinct "CLICK" sound.

Look at the screen and type the following but don't press ENTER yet.

OUT160,0

Put the laptop to your ear again.  Listen while you slowly press the ENTER key
down.  You should hear a distinct "CLACK" sound.

If you got both the "CLICK" and the "CLACK" sounds, we've confirmed that one of
the two involved relays works - so proceed.  Elsewise you've found one problem
- proceed anyway.

Look at the screen, type the following but don't press ENTER yet.

OUT178,12

Put the laptop to your ear again.  Listen intently with no distracting sounds
in the room.  Slowly press ENTER.  You should detect a soft "Tink" sound.

Look at the screen, type the following but don't press ENTER yet.

OUT178,4

Put the laptop to your ear again and listen intently.  Slowly press ENTER.  You
should detect a soft "Tonk" sound.

If you got both the "Tink" and the "Tonk" sounds, we've confirmed that the
second and more important relay works.

If both relays worked, now we deal with your modem cable and your telephone
"instrument".  Hook up the Direct Connect modem cable.  This means connecting
the laptop end AND BOTH CABLES: one is GREY; other is BROWN.  GREY cable
connects to your telephone "instrument".  BROWN cable connects to the telephone
line.

Set the DIR/ACP slide switch (on left side of laptop) to DIR position (Direct
Connect modem cable).  Lift the "instrument" handset and put it to your ear.
You should hear dial-tone, compliments of your telephone company.  This is
evidence of a "line seizure".  While listening to dial-tone, type OUT160,1 and
press ENTER.  You should hear nothing because the first relay disconnected the
instrument.  Quickly type OUT160,0 and you should again hear the dial-tone
unless the telephone company got bored waiting for something to happen on your
phone line.

Hang up the instrument.  Again, lift the instrument handset, pout it to your
ear and enjoy another dial-tone.  Type OUT178,12 and when you press the ENTER
key you should notice a slight (3 DB) reduction of loudness in the dial-tone.
Next, type OUT178,4 and the loudness of the dial-tone should return to full
loudness.
---------------------------
Somewhere in these tests you'll find a failure.  If not then I'm confused!
Perhaps I'm confused and think you have a Direct Connect modem cable while you
actually have something else (acoustic connector, etc).  Perhaps I'm confused
and think you have a telephone instrument while you actually have something
else (that headset you mentioned which you rigged up in some fashion).  I could
be confused about other things.

At any rate, you now have a low-tech series of tests.  So do 'em and see what
are the results.  By the way Mike, your last message said that as soon as you
plugged in the modem cable you heard (via that rigged headset) that "it"
(assumed to be the telephone line) went into line seizure (assume you heard
dial-tone).  If that's true, note that it's indicates proper operation.  Some
Direct Modem cables include an end-cap which extends the pnone line toward the
telephone instrument when detached from the laptop.  In other words, the
end-cap provides the same line-to-instrument extension that otherwise is
provided by the first (CLICK/CLACK) relay, compliments of no power to the relay
coil.  So if this doesn't happen where you try it on the "other Model 100" then
that laptop has a problem involving its first relay.