128 lines
4.8 KiB
Plaintext
128 lines
4.8 KiB
Plaintext
*************************************************************************
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How to upgrade your 24oo modem into a 96oo baud. (US Robotics compatible
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of course)
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Written By
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Death Bringer (CPT/Info-Net/IRA)
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06/7/91
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Be sure to turn off your modem before you begin.
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First of all, you need to go to your nearby electronics store, don't try
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to go to Radio Shack, their parts have their own model numbers and you'll
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have a hell of a time getting the parts you need. This upgrading of your
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modem will not work on old hayes modems, but they will work on any clone
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maker of modems (everex, practical peripherals, anchor, ati, intel, etc.)
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It will only work with modems with the Intel Chipset.
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This technique widens the band width by using a different chip that is
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similiar to the chip already in your modem.
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Parts Needed:
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16550 UART
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L4313545 IC
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SC11020CN IC
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L8730183 IC
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First of all, check to see if your biggest chips are soldered or socketed.
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if they are soldered, you'll have to de-solder the chips before you begin.
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After you get that done, replace the 8250 UART with the 16550 UART. (16550
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UARTs are required for 9600+ speeds). The other 1 or 2 chip(s) need(s)
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to replaced with INTEL L4313545 instead of the chip that is already there.
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If your modem has another socket or more, than you are in luck, you can
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purchase a chip from US Robotics, and make your modem faster than 9600.
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If you don't have the socket, than you can only go 9600. I'll get the
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chip number to you in the next edition and explain how and where to
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install it. I am working on a way for the people (like me) that do not have
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the extra socket in their modem to speed up the rates. I am working on a way
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to piggy back the chip. I'll get back to you. There should be a 22 pin
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chip on your modem also with a model number of SC11005CN or some where close
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to it. Replace it with the SC11020CN. Also, replace the L8630173 with the
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L8730183 chip. If you have any suggestions or questions, you can locate me
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through Compuserve USER ID 74702,97524
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*****OPTIONAL, LAP-M Error correction*****
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Adding error correction is rather simple. For this these parts are
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necessary:
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Potentiometer. This is a 5k audio taper variable resistor.
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Capacitor. Any non-polarized 1.0 to 1.5 uf cap should do.
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100 ohm resistor - quarter or half watt.
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Wire
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Solder, soldering iron, etc.
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Solder one end of the capacitor to PIN 1 of the phone line input jack
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|-------------------|
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| \ line in ::
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| \ phone in ::
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|-----------||||||||| pin 1^
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If your modem is external, the diagram looks like this.
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|------------------|
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| /|
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| ||RS-232 port
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| \| ::
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| |-|line in ::
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| |-| pin 1^
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| |-|phone in
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| |-|
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|------------------|
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This should be on the back of the modem.
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Pin one should the farthest on the bottom left.
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Solder the other end of the capacitor to the center lug of the potentiometer
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(there are three lugs on this critter). Solder one end of the resistor to the
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PIN 4 of the line input jack. Solder the other end of the resistor
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to either one of the remaining outside lugs of the potentiometer. Doesn't
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matter which one.
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-------------------------------------------------------------------------
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ADDITION TO ORIGNAL FILE - 6/15/91
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Bill McCauley & Dark Spyre/Dr. Brains/Ryan Schwartz/Lamer/Loser
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First, a personal recomendation. _THIS WORKS!!!_ I have been plagued with
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2400 baud for some time. I hate waiting for the transfer to finish so that
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i can use the phone. Threw the gismo together in about 10 or 15 minutes,
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took another five to adjust the pot for best results on my worst
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conection, and guess what? No more slow connections!
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-------------------------------------------------------------------------
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Have Fun!
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I am working on cheap ways to install V.32/V.42bis on your modified modem
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*************************Updated, 6/16/91********************************
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Installing V.42bis:
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1) You will need to purchase a 27C512 ROM chip.
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2) You will need to purchase a Sony CXK58257P-12L (or equivalent) Ram chip.
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3) Install the Rom in the Supervisor (SUP) socket.
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4) Install the Ram in the Ram socket.
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5) Make up two 3 pin jumpers for P9 and P10 with pins 1 and 2 jumpered
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on one and pins 2 and 3 jumpered on the other. Connect the vacant pin 1
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on the one to the vacant pin 3 on the other with a jumper wire.
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6) Remove the jumpers on P9 and P10.
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7) Install the jumper with pins 1 and 2 connected together on P9.
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8) Connect the jumper with pins 2 and 3 connected together on P10.
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DeathBringer '91
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