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.