2400/9600 BPS Faxmodem (250-3027B) Troubleshooting Faxback Doc. # 5752 When you have problems transmitting data with your modem (garbled data, intermittent errors, and so on), check to see that: -The phone connection is clean and noise-free. -No one is talking on the telephone line. -The phone and all extensions are on the hook -The operation speed is correct for the modem you are using and the modem with which you are communicating. If you still cannot transmit data, disconnect your modem to see if the phone line is operating correctly. If it is, the trouble is probably in your modem. At this point, you can try some of the remedies listed below or take it to your local Radio Shack store for further testing or repair. To test the mode, use your communication software in the command (local or terminal) mode. In the mode, your keyboard acts as a dumb terminal's keyboard talking to the modem. Once you are in the command mode, you can send commands and start testing your modem. PROBLEM: You cannot install your modem correctly. SOLUTIONS: The first step to solve the above problem is to verify communications between your modem and your PC. Load your communication software and enter the command mode and type capital ATZ, and then the carriage return key. TYPE: ATZ Depending on your communication software, you receive an 0 or an OK response. If you do not see the ATZ, but you get to 0 or OK on the screen, this is normal. Your software has initialized the modem using the E0 command (not echoing the command characters). You can type ATE1 to activate the echo so you can see what you have typed. If you do not see any result code for your ATZ command, do not be concerned. Your modem was tested at the factory before shipment. Difficulties often occur during the installation of a modem that reveal an existing problem in your PC. The most common problem is a conflict among the devices installed in your PC. The solution might be as simple as changing the dip switch setting of the modem. Add-on cards such as modems, serial or multifunction cards communicate with the computer by means of communication (Com) ports and by sending interrupt (IRQ) signals to the PC. Com ports share the same interrupt. Com1 and Com3 use IRQ4, while Com2 and Com4 share IRQ3. In most cases, modems CANNOT share an IRQ with another device. Therefore, your modem should be set to exclusive Com/IRQ combination. For example, if you have a mouse on Com1, set your modem to Com2 or Com4 (See the Com port switch setting table on Page 9). Refer to the manuals for your PC and mouse card or other peripheral devices installed on your computer to determine their Com port settings. Then set your communication software and your modem to a Com port which is not assigned to any other device. -Some PCs display this information during the boot-up process. Follow results from the PC during this process and not the available Com ports. -You can run the DOS command MODE to locate the available Com ports. SETTING COM PORTS FOR YOUR INTERNAL MODEM For the new setting to take effect, first turn off your PC. If your PC has a multifunction card and it has an optional unused serial port, we recommend that you disable that unused Com port. Refer to the card's manual for the proper jumper/switch setting. Check the dip switches of your modem and select a com port which has not been assigned to any other device. Set your communication software to the same Com port setting that you have selected for your modem. Turn on your PC and load your communication software to test the modem. SETTING THE MODEM TO A VALID SPEED If all the above items are set correctly, and you still don't get a result code, check the speed setting of your software, and set it to a valid speed which is supported by your modem. PROBLEM: THE MODEM DOES NOT DIAL SOLUTION(S): Make sure that you can communicate with your modem as described above, then check the following: -Make sure that your modem is connected to a live phone line, and that the modem volume setting is not too low to be heard. -Issue the ATL2 command for medium speaker volume. -Check the speed setting of your software, and set it to a valid speed which is supported by your modem and your communication software. -Check the DTR setting. Refer to your software manual for the correct setting. PROBLEM: THE MODEM DIALS BUT DOES NOT CONNECT. SOLUTION(S): The remote modem might not recognize your modem's speed. This can happen when you call a modem that does not have auto speed detect. -Change your speed setting. -Change the state of DTR. To change the state of the DTR, use the AT command AT&Dn, n being a valid parameter. -Your might have a noisy phone line. check toe line with a regular telephone, If it is bad, notify your local telephone company. -Your phone cord may be bad. Check it by plugging it into a regular telephone set and listening for a dial tone. -If you are using a PBX telephone line, you might need to use a prefix digit(s) and a comma when issuing a dial command. For instance, if your PBX requires that you dial 9 for an outside line, you should type a 9 and then a, (the comma allows a 2 second pause), then the number you are trying to dial. For example: ATDT9,5551212 PROBLEM: BURSTS OF GARBLED CHARACTERS DURING THE COMMUNICATION & FILE TRANSFER SESSION SOLUTION(S): -Make sure your telephone line is used ONLY by your modem. -If your telephone line has a call-waiting feature, disable it by issuing the command: ATDT70*555-1234 when dialing out. Some telephone companies use different codes for disabling and enabling a call-waiting. If this one does not work, contact them for more information. -Your connection might be poor. Terminate the call and try again. PROBLEM: DIFFICULTIES IN TRANSFERRING FILES SOLUTION: -Use the same file transfer protocol as the remote modem. PROBLEM: YOU HEAR A HIGH PITCH TONE WHEN YOU ANSWER YOUR PHONE SOLUTION(S): Your modem is auto-answering the calls. -Set Auto Answer to off by issuing the ATS0 command. PROBLEM: YOU CANNOT TERMINATE A COMMUNICATION SESSION SOLUTION(S): To terminate a communication session, follow these steps: 1. Type +++ to enter command mode, wait for an OK response 2. Type ATH0 Refer to the AT Command section for details on the &Cn and &Dn settings. LIGHTENING Your modem has protection circuits, which meet or exceed FCC requirements, to reduce the risk of damage from surges in telephone and power line currents. However, lightning striking near or on these lines can damage the modem. Lightning damage is uncommon. However, if this concerns you or if you live in an area with frequent and/or severe electrical storms, we suggest that you unplug your electronic equipment during storms. DIAGNOSTICS Your modem has built-in diagnostic capabilities. Test patterns for the analog loopback can be generated by either the modem or the computer. You use the test commands (&T) outline in "Modem Test Command" to perform these tests. The modem does not respond to an incoming call while in the diagnostic mode. (smc-12/16/93)