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- Copy(c)right 1986,1994 by Gary Raymond, New Orleans, La.
- Port Swapper Program V1.1
-
- Gary Raymond
- POB 8184
- New Orleans, La. 70182
- Tech Help (504) 288-6550
- Compuserve 70613,3165
-
- ====================================================================
- Files Provided:
- SWAPORTS.COM Serial Port SWAP Utility.
- SWAPORTS.DOC This document.
-
- Why SWAPORTS? The purpose of this utility is to allow bios serial
- communications programs that can only access COM1 or COM2 ports to
- function properly on serial PC modem hardware set to COM3 or COM4.
- SWAPORTS does this by poking the correct port addresses directly into
- the proper places in BIOS memory. It can even correct problems with
- serial software that claims to work on com3 and 4, but gives strange
- symptoms instead, such as receiving ok but being unable to send.
-
- QUICK FIX: Before proceeding, try SWAPORTS 7. This restores all
- standard IBM port addresses into their normal BIOS memory slot
- locations. It will generally cure most wierd troubles associated with
- using either com3 or com4 on BOTH software and hardware.
-
- Any program that bypasses DOS and BIOS and directly addresses the COM
- ports will not be affected in any way by SWAPORTS. Many newer modem
- programs bypass DOS in order to achieve higher port speeds or the
- ability to multitask. The type of programs that bypass DOS and
- address the ports directly are never a problem. Rather, it is the
- others, that call upon DOS or BIOS services, that SWAPORTS can help.
-
- Example, suppose you have a serial program (using BIOS calls) that
- can only be set to use com port one or two. Your mouse and modem are
- set for com1 and com4 respectively. Because of the mouse, your only
- option is to use com2 in the serial program, but, your hardware is
- rigged to com4. What you now need is to swap com two's address with
- that of com4. SWAPORTS option 6 will do it!
-
- Another possibility; your hardware is set for com3, your mouse
- is set on com1. Your serial program is set for com2. In this case
- you must (if possible) set the program's IRQ to 4 in place of 3 (to
- avoid mouse conflicts), and use SWAPORTS option 2.
-
- Next example. Your modem is set for com4. Your software is supposed
- to work on com4. It does not. It works ok on received characters but
- does not transmit characters. One reason may be the method the code
- relies on to operate. It may use interrupt services to receive but
- bios (dos) services to send. The interrupt service routine probably
- uses direct port addressing whereas the send function requires
- locating the correct address in bios segment 40, offset 6. In
- this case, the correct address (2E8 hex) may not exist anywhere else
- in the bios area so swapping is useless. Function 7 is the answer. It
- sets all standard addresses into bios.
-
- Some AT computer BIOS systems assigns logical COM ports from low too
- high, to all responding I/O ports in order as they are found. Non
- responding I/O ports are skipped. If you had only one COM port, and
- it was the address for COM2, your computer BIOS would assign it to
- COM1 because no other real COM1 address was present. In this case
- you effectively already have a one-two swap.
-
-
- Standard IBM serial port addressing scheme:
-
- BIOS ADDRESS
- SEG :OFF
- 0040:0000 0040:0002 0040:0004 0040:0006
- COM1 = 3F8 COM2 = 2F8 COM3 = 3E8 COM4 = 2E8"
-
-
- DISPLAY HELP by typing SWAPORTS alone without a parameter number.
- You will see the following help information.
-
- The Correct Syntax is SWAPORTS # (i.e. SWAPORTS 7)"
-
- 4 = SWAP PORT 1 with PORT 2"
- 5 = SWAP PORT 1 with PORT 3"
- 1 = SWAP PORT 1 with PORT 4"
- 2 = SWAP PORT 2 with PORT 3"
- 6 = SWAP PORT 2 with PORT 4"
- 3 = SWAP PORT 3 with PORT 4"
- 7 = SET ALL PORTS TO IBM DEFAULTS"
-
- NOTE: Swapping ports three and four is ineffective"
- below DOS Version 3.3"
-
- There are many things that can go wrong after installing a modem on
- your computer. Usually, problems are evenly divided between hardware
- and software configuration errors. In general, the modem itself must
- be mechanically set, via jumper pins or dip switches, to address
- whatever available serial port is usable on your PC. The selected
- port must also be paired with an interrupt request line (IRQ). No two
- serial devices (examp: modem and mouse) may share actively the same
- serial port IRQ address.
-
- The original IBM PC architecture supported only two COM ports. Soon,
- clone makers, and eventually IBM, added more serial capability.
- Still, there are no standard addresses or IRQ (Interrupt Request)
- lines for the additional ports. The addresses for COM1 and COM2 are
- 3F8h and 2F8h, respectively, with COM1 on IRQ4 and COM2 on IRQ3.
- When you install more serial ports, COM3 usually uses 3E8h and IRQ4,
- while COM4 uses 2E8h and IRQ3.
-
- DOS gets its I/O information from BIOS, which determines what's
- installed where in your system during the POST test (Power On Self
- Test. Most POST operations check only for the first two installed
- ports. To get around this problem, communications software and some
- serial peripherals (such as mice) will occasionally support higher
- COM ports by DIRECT addressing, rather than making DOS function calls
- to determine the port addresses. Remember, your computer BIOS (during
- POST) assigns logical COM ports from low too high, to all responding
- I/O ports in order as they are found. Non responding I/O ports are
- skipped. Thus if you have only one COM port, and it was the address
- for COM2, your computer BIOS would assign it to COM1 as no real COM1
- address was present.
-
- Keep in mind, however, that you probably won't be able to swap two
- ports that share the same IRQ (such as COM1 and COM3) if say, you
- happen to have a mouse attached to one of them. This is because the
- system will get confused when the interrupt triggers.
-
- ====================================================================
-
- ┌─────────┐
- │ MEMBER │ Society of
- │ ┌──────┴──┐ Independent
- │ │ │ Shareware
- └──┤ ■ │ Authors
- │ ║ │
- └────╨────┘
- This program is produced by a member of the Society of Independent
- Shareware Authors (SISA). The Society wants to ensure that all
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- ====================================================================
-
- WARRANTY:
- Software:
- Gary Raymond warrants that the software contained herein will
- perform in substantial compliance with the documentation
- accompanying the software. If you report, in writing, a significant
- defect to us, and we are unable to correct it within 90 days of the
- date you report the defect, you may return the software and
- accompanying materials, and we will refund the purchase price.
-
- Diskette's and Documentation:
- Gary Raymond, warrants all diskette's and documentation to be
- free of defects in materials for a period of 30 days from the date
- of purchase. In the event of notification within the warranty period
- of defects in any materials, Gary Raymond will replace the
- defective diskette or documentation.
-
- Remedies:
- The remedy for breach of the warranty shall be limited to
- replacement and shall not encompass any other damages, including but
- not limited to loss of profit, special, incidental, consequential,
- or similar damages, losses, or claims.
-
- DISCLAIMER:
- Gary Raymond specifically disclaims all other warranties,
- expressed or implied, including but not limited to, implied
- warranties of merchantability and fitness for a particular purpose
- with respect to defects in the diskette and documentation, and the
- program license granted herein, in particular, and without limiting
- operation of the program license with respect to any particular
- application, use, or purpose. In no event shall Gary Raymond be
- liable for any loss of profit or any other commercial damage,
- including but not limited to special, incidental, consequential or
- other damages.
-
- GOVERNING LAW:
- This statement shall be construed, interpreted, and governed by the
- laws of the State of Louisiana.
- ====================================================================
-
- Registering your copy will help continue the competitive advantages
- of providing economical shareware.
-
- Yes Gary, I enjoy your program and would like to register and
- obtain the latest version. SWAPORT V11
-
-
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-
- City & State ___________________________________________________
-
- ZIP _____________________________ Phone _________________________
-
- Send $4 + $1 (ship & hand) check or money order to:
-
- Gary Raymond
- POB 8184
- New Orleans, La. 70182
- Tech Help (504) 288-6550
- Compuserve 70613,3165
-
- ================================[EOF]===============================
-