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- PORTSET Documentation.
-
- Written by Herb Rose, 23 Sept 1991.
- Placed into the public domain by Herb Rose, 23 Sept 1991
-
- PORTSET is a DOS utility for sending text to a specific serial port.
- It was written as a support utility for Falken BBS. To use SETPORT,
- simply enter the SETPORT command at the DOS prompt. The required
- command line parameters are :
-
- SETPORT <port> <baud> <text>
-
- where :
-
- <port> is the serial port you wish to send text to. This may be
- COM1, COM2, COM3, COM4, or the actual address of the serial
- port. COM1-COM4 correspond to addresses 3F8, 2F8, 3E8, 2E8,
- respectively.
-
- If you have a multiport card installed, and wish to configure
- the ports on that card, you would issue a separate SETPORT
- command for each port on the card. These normally start at
- address 100 and go up from there. i.e.
- SETPORT 100 2400 "atz\r" would send the string atz<CR> to
- the serial port at address 100, at 2400 baud.
-
- <baud> is the baud rate to set the serial port for. The port is
- left configured to this baud rate after SETPORT runs. The
- legal values are : 300, 1200, 2400, 4800, 9600, 19200.
-
- <text> is the actual text you wish to send to the serial port.
- I recommend enclosing the text in quotes. This keeps the
- text together as one text string, even if there are spaces in
- the text. Modem commands should end with a \r which is
- interpreted as a Carriage Return ( ENTER key ). Modems will
- not execute commands until the \r is sent.
-
- Special characters recognized :
- \r = carriage return, hex 0D
- \n = line feed, hex 0A
- \^ = put a caret (^) in the text
- ^x = where 'x' is any character - place a control character
- in the text. i.e. ^M is ctrl-M, or carriage return.
- To place the ^ in the text, use \^.
-
-
- Example :
-
- To set a 2400 baud modem for Falkens suggested modem configuration...
-
- PORTSET COM1 2400 "ATE0 S0=1 S2=1 V1 &C1 &D2\r"
-
- AT : the modem attention signal. Tells the modem that commands follow.
- E0 : turn off local echo from the modem.
- S0=1 : answer phone after 1 ring
- S2=1 : set modem escape character to hex 01
- V1 : use verbose (text) result codes.
- &C1 : DCD signal follows carrier detect
- &D2 : Modem resets and enters Command Mode when DTR goes high
-
- The modem should respond with 'OK' after processing this command text.
-
- As you can see, the main purpose of this program is to configure modems
- from the command line. Many modems on the market now have Non-Volatile
- RAM (NVRAM) where configurations may be stored even if the modem is
- powered off. This utility allows you to set the configuration you desire
- in the modem, and save it to NVRAM. This is normally done with the &W
- command. The configuration can then be recalled from NVRAM simply by
- resetting the modem with the Z command ("ATZ\r").
-
- PORTSET does not use serial interrupts. It accomplishes it's task using
- polling techniques. It should not interfere with any installed serial
- drivers, or with any other resident programs that I am aware of. It may
- not work correctly with some multitaskers, because it uses the DOS
- timer interrupt to control it's polling routine.
-
- Some PCs are slower than others. In general, there should be no problem
- running PORTSET on any computer at speeds up to 19200. If you have an
- XT running at 4.77 mhz, you may have to limit the baud rate to 9600 for
- reliable data exchange.
-
- PORTSET performs the following functions :
-
- 1. Determines if a UART actually resides at the specified port
- address. To determine this, PORTSET attempts to place the UART
- in Local Loopback mode. It then toggles the DTR and RTS bits
- of the Line Control Register. If there is an 8250-type UART
- at that address, the DTR and RTS bits will be reflected in
- the DSR/CTS bits of the modem status register during loopback.
- If the DSR/CTS bits do not correspond with the DTR/RTS bits,
- then either there is no UART there, or it is not working.
- 2. Turns interrupts off for the specified port.
- 3. Sets the port for 8 bits, no parity, 1 stop bit.
- 4. Sets the baud rate for the port.
- 5. Lowers DTR and RTS signals. Some modems are configured to enter
- Command Mode when DTR goes low.
- 6. After a 2 second pause, RTS and DTR are raised again.
- 7. The text is transmitted to the modem, and all characters received
- from the modem are echoed to the screen. A 5 second interval is
- used to get data from the modem.
- 8. The interrupt enable, line control, and modem control registers
- are restored to their original conditions.
-
-
-