9600 BPS Faxmodem (250-3029) Jumpers Faxback Doc. # 5222 ABOUT IRQ2 AND IRQ5 Most internal serial devices support only IRQ3 and IRQ4 interrupt request lines in your computer. This limits your computer's use of serial devices because four communications ports (COM1 through COM4) must share two interrupt request lines (IRQ3 and IRQ4). To give you maximum flexibility, this fax/modem supports two additional interrupt request lines, IRQ2 and IRQ5. The following example shows how you can use IRQ2 and IRQ5. Assume that your computer has a serial mouse configured as COM1 and a serial printer configured as COM2, and that you want to use your fax/modem while printing in the background. You cannot perform this task with most modems or fax/modems because setting the fax/modem to COM3 (which uses IRQ4) conflicts with the mouse at COM1 (which also uses IRQ4), and setting the fax/modem to COM4 (IRQ3) conflicts with the printer at COM2 (IRQ3). Your fax/modem solves the problem by allowing you to use two additional interrupts (IRQ2) and IRQ5), which effectively adds up four additional COM port addresses. This means that you can have, for example, a mouse configured as COM1, print in the background using COM2, and download a file from a bulletin board--all at the same time! IMPORTANT: Using these interrupts can be tricky, so only use them if you have no other choice. Not all computers or DOS versions support serial devices on IRQ2 and IRQ5. Generally, you can set up your internal fax/modem to use IRQ5 if your computer is compatible with the IBM/PC/AT standard and it does not have a parallel port set up as LPT2. Similarly, you can use IRQ2 if your computer is compatible with the IBM/PC/XT standard and you do not have another device that uses IRQ2. Note that some bus mouse devices and tape backup drives use IRQ2. Check with your computer dealer or your computer owner's manual for further assistance. SETTING THE COM PORTS To change the fax/modem COM setting: * Decide which COM port address is appropriate for your internal fax/modem. * Locate the three red COM port jumpers. You will find them near the center of the board, above the gold-plated edge connector that is near the center of the bottom of the board. (see Figures C-6 and C-7). INTERNAL FAX/MODEM JUMPERS After you determine the appropriate COM port setting, set the jumpers as shown: TO SELECT COM1 COM1 OR 3 H x x o COM2 OR 4 I o o o COM3 OR 4 F o x x COM1 OR 2 COM2 OR 4 G o x x COM1 OR 3 TO SELECT COM2 COM1 OR 3 H o o o COM2 OR 4 I x x o COM3 OR 4 F o x x COM1 OR 2 COM2 OR 4 G x x o COM1 OR 3 TO SELECT COM3 COM1 OR 3 H x x o COM2 OR 4 I o o o COM3 OR 4 F x x o COM1 OR 2 COM2 OR 4 G o x x COM1 OR 3 TO SELECT COM 4 COM1 OR 3 H o o o COM2 OR 4 I x x o COM3 OR 4 F x x o COM1 OR 2 COM2 OR 4 G x x o COM1 OR 3 COM 5 (COM3/IRQ2) COM1 OR 3 H o o o COM2 OR 4 I o x x IRQ2 IRQ5 J o o o COM3 OR 4 F x x o COM1 OR 2 COM2 OR 4 G o x x COM1 OR 3 COM6 (COM4/IRQ2) COM1 OR 3 H o o o COM2 OR 4 I o x x IRQ2 IRQ5 J o o o COM3 OR 4 F x x o COM1 OR 2 COM2 OR 4 G x x o COM1 OR 3 COM7 (COM3/IRQ5) COM1 OR 3 H o o o COM2 OR 4 I o o o IRQ2 IRQ5 J x x o COM3 OR 4 F x x o COM1 OR 2 COM2 OR 4 G o x x COM1 OR 3 COM8 (COM4/IRQ5) COM1 OR 3 H o o o COM2 OR 4 I o o o IRQ2 IRQ5 J x x o COM3 OR 4 F x x o COM1 OR 2 COM2 OR 4 G x x o COM1 OR 3 SETTING IRQ2 AND IRQ5 IMPORTANT: Remember that using these interrupts can be tricky, so only use them if you have no other choice. IMPORTANT: Selecting IRQ2 and IRQ5 does not actually create new COM ports. The designations COM5 through COM8 are merely convenient designations used by software that supports this feature. If you changed the internal fax/modem COM port and/or IRQ setting, you must also change the setting of your communications and fax software (refer to the manual that accompanied your software for more information). SETTING THE WAIT STATE (OPTIONAL) Your internal fax/modem has a programmable "wait state" that can increase the reliability with computers that have a very fast data bus speeds. IMPORTANT: Don't confuse clock speed with data bus speed. Most computers, even those with very fast clock speeds (such as 25 or 33 MHz), do not have data bus speeds exceeding 10 MHz. If you computer has a data bus speed over 10MHz, it may be trying to obtain information faster than your internal fax/modem can provide it, creating the possibility of an error. To avoid any chance of error, you can adjust the wait state. The wait state sends a signal to the computer to "give it more time." Your fax/modem is shipped with the "Wait 0" setting in effect. If you install the fax/modem in a computer with a data bus speed that exceeds 10 MHz, we recommend that you set your fax/modem for "Wait 1" by moving the K jumper as shown in Figure C-12. FOR WAIT0: (default) FOR WAIT1: K o x x K x x o CONFIGURING YOUR FAX/MODEM FOR USE IN JAPAN (OPTIONAL) If you will be using your fax/modem in Japan, find the P2 jumper (see Figure C-13). Then remove the jumper from the center and right pins and push it onto the left and center pins. This will change the fax/modem signal level to meet Japanese requirements. OTHER INTERNAL FAX/MODEM JUMPERS The internal fax/modem has two other jumpers, which must be left in their original factory positions. They are not user-configurable. Leave the P3 jumper on the center and right pins. Leave the P4 jumper in the "B" position if the nearby large chip says "C1993." Leave the P4 jumper in the "A" position if the nearby large chip says "C1999." (dtc-07/29/93)