COURIER HST APPENDIX D PROBLEMS AND SOLUTIONS You may occasionally encounter one of the problems listed here. They are divided into two categories: before and during the exchange of user information over the data link. ----------------------------------------------------------------- PROBLEM SUGGESTED SOLUTION ----------------------------------------------------------------- Before Establishment of the Data Link ----------------------------------------------------------------- Your modem . . . Doesn't answer the phone or go "off hook" to dial a number Check to make sure your computer or terminal is sending a Data Terminal Ready (DTR) signal via the RS-232C interface. See Appendix B-1 and Appendix B-3, DIP switch 1. Doesn't respond OK when you type AT 1. Make sure you're typing in either upper case or lower case letters, not a combination, and that you press the Enter key. 2. If you're using a computer, make sure it is in Terminal Mode. 3. Check to see that your terminal or software is set to the correct bit rate and word length (7 bits with or without a parity bit, or 8 bits and no parity). If you're using a computer, make sure your software is set to the correct communications port. 4. Check that DIP switch 3 is DOWN, for result code display, and that DIP switch 2 is UP, for verbal result codes. If not, change the switch(es) and issue ATZ . Or issue whichever of these commands is needed: ATQ0 (to display the message) ATV1 (to display a verbal message) 5. Your machine may require the Carrier Detect override (DIP Switch 6 DOWN), but you've changed the factory setting. Check Appendix B-3. 6. A rare condition is that your terminal/computer reverses the send/receive functions at the RS-232C interface. See Appendix B-1, Appendix B-3, Quad switch, and your equipment documentation. D-1 COURIER HST ----------------------------------------------------------------- PROBLEM SUGGESTED SOLUTION ----------------------------------------------------------------- Before Establishment of the Data Link ------------------------------------- Your computer . . . Reacts as though a data link has been established, but no call has been received DIP Switch 6 is set DOWN at the factory for Carrier Detect override, but your system may be reacting to improper signals received at the RS-232C interface. Set DIP switch 6 UP (OFF). When the modem is in Answer Mode, acts as if a Carriage Return has been entered, but nothing has been typed at the keyboard Your software may be misreading signals from the modem as it automatically sends a Carriage Return and a Line Feed before and after the RING and CONNECT messages. Entering the Quiet Mode command, ATQ1 , should solve the problem. Both modems . . . Exchange carrier signals, but fail to establish a communications link 1. Check to make sure the proper bit rate, word length, parity and number of Stop bits have been selected. 2. If that doesn't correct the problem, it's likely that the quality of the phone connection is poor and that the other modem is missing the signals your modem is transmitting. The variable quality of phone line connections may be due to any number of conditions in the phone service's equipment or the current environment. Try several calls, and if you still can't get through, try calling another modem. If the second modem accepts your call, the problem may lie with the modem you first tried to call. 3. Make sure the modem at the other end of the line is USR-HST compatible at 9600 bps, V.22bis-compatible at 2400 bps, Bell 212A-compatible at 1200 bps, or Bell 103-compatible at 300 bps. These are the common signaling standards for full duplex dial-up network transmission in the U.S. ----------------------------------------------------------------- PROBLEM SUGGESTED SOLUTION ----------------------------------------------------------------- D-2 COURIER HST During Data Transfer ----------------------------------------------------------------- Your screen displays . . . Only brackets Check to make sure both modems are at the same bit rate, word length, parity and number of Stop bits. If the settings are correct, the problem may be with the phone line. Try the following measures: 1. Try placing the call again. The phone company routes even local calls differently each time you call. 2. Try calling a different modem to see if the problem persists. (However, if it does, the problem may still be with the phone line.) 3. If you are using a long-distance service and the problem persists, you might try using a different service. Random (garbage) characters Make sure both modems are set at the same bit rate, word length, parity, and number of Stop bits. Double characters The modem's online local echo is probably ON. Return the modem to Command Mode (use +++) when it's convenient, and then type: ATF1 ----------------------------------------------------------------- IF YOU STILL HAVE PROBLEMS The problems described above are by far the most common ones that users encounter. If the suggestions we've given don't clear up your difficulties, try the following: 1. Review the manual carefully to see if you've missed something. 2. Call or visit your dealer. Chances are your dealer will be able to give you the assistance you need. This is much more efficient and time-saving than returning the modem to USRobotics. D-3 COURIER HST 3. If your dealer can't clear up your difficulties, call the USRobotics Technical Support Department at 800/982-5151 (in Illinois, 312/982-5151). Our Service Representatives will be happy to give you assistance over the phone Monday through Friday from 8:30 a.m. to 5 p.m. (Central Time Zone). 4. If necessary, the Service Representative you talk to may give you a Return Materials Authorization (RMA) number. Modems without an RMA number will not be accepted. 5. If you do return the modem to us, please follow this procedure -- a. Ship the unit, postage paid, in its original container. If the original container is not available, pack the modem carefully in a strong box of corrugated cardboard with plenty of packing material. b. Be sure to include your RMA number inside the package, along with your name and address. Put your return address and your RMA number on the shipping label as well. c. Ship the well-packed modem to the following address. Technical Support Department USRobotics, Inc. 8100 North McCormick Boulevard Skokie, Illinois 60076 d. Please note that USRobotics will not accept packages sent COD, so be sure to send the modem postage paid. e. USRobotics will repair your modem and return it to you via United Parcel Service. D-4