Cable modem/DSL users: see Navas Cable Modem/DSL Tuning Guide^TM

H. BRAND-SPECIFIC INFORMATION

Posted as <http://modemfaq.navasgroup.com/faq_h.htm>.

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Contents

• A. TROUBLESHOOTING
• B. GENERAL INFORMATION
• C. MODEM FEATURES
• D. ADVANCED TECHNOLOGIES
• E. MICROSOFT WINDOWS
• F. PURCHASING
• G. NON-MODEM DRIVERS
• H. BRAND-SPECIFIC INFORMATION
• Any other 3Com/USRobotics tips?
• Where can I get information on my Rockwell-based modem?
• I. MODEM COMPANIES ON THE INTERNET

Any other 3Com/USRobotics tips?

• Certain 28800 Sportster models can be inexpensively upgraded to 33600 (including Selective Reject). See "Sportster Supervisory Update Information" (Note: the dates in the firmware table are not necessarily the dates of the latest versions.)
• Useful modem commands:
• ATI6, issued after a disconnect, will tell you the reason for the disconnect. Disconnect reasons are explained in the Courier manual.
• ATI6 will tell you your current modem-to-modem connection speed if you escape (e.g., with "+++") to command mode while online. With split/asymmetric speeds (see What are split/asymmetric speeds?), ATI6 will report the two speeds as receive/transmit. (See also "Why can't I get back on-line after I escape to command mode?" To display the current connection speed when using Trumpet Winsock on a SLIP/PPP link, see "Any Trumpet Winsock tips?")
• ATO will return you to on-line mode after you escape to command mode; ATO1 will also request a retrain (which may help if line conditions have changed substantially).
• ATI7 will tell you what firmware version (date) you have.
• For a good description of the output of the ATI6 and ATI11 commands, see the FAQ by USR UK.
• If you are running Windows 95/98, the output of all the ATIn commands can be easily displayed with Modem Diagnostics. (See "Any Windows 95/98 tips?")
• If you experience problems connecting to certain V.34 modems:
• It may help to disable the 3429 symbol rate (S54.5=1), which confuses certain modems (e.g., Hayes) that are not fully V.34 compliant during negotiation.
• It may help to disable V.FC (S56.7=1).
• It may help to disable V.42 detect phase (S27=48).
• If you experience problems connecting to certain V.34/V.FC modems, or you otherwise want to connect with V.FC when the remote modem supports both V.34 and V.FC, disable V.8 (S54.7=1), which effectively disables V.34.
• If you have a particular number where you sometimes connect at a very slow speed but get a much higher speed when you immediately redial, find out if there is a Hayes modem at the other end. If so, it may be possible to correct the problem by updating the Hayes firmware.
• If you experience problems connecting to certain older MNP modems (esp. at 2400 bps), try S15=64. This option is only documented for the Courier ("Unusual MNP-Incompatibility"), but may work for the Sportster as well.
• If you hear a strange ringing sound after dialing and before the remote answers, that's Call Indicate. It's a good idea to disable it (S54.6=1), because it can cause connection problems with certain modems.
• Some users have reported that resetting the modem before each call improves the chances of a good connection. To do this, use ATZn instead of AT&Fn. The options for ATZn are:

Z - reset and load profile Yn
Z1 - reset and load profile 0
Z2 - reset and load profile 1
Z3 - reset and load &F0 defaults
Z4 - reset and load &F1 defaults
Z5 - reset and load &F2 defaults
In other words, ATZ4 is a good alternative to AT&F1. Generally the only problem is that you can't put more commands on the same line with ATZn as you can with AT&Fn; e.g., you can do AT&F1S11=55 but not ATZ4S11=55. If you have a comm program that can issue more than one initialization string (e.g., HyperACCESS for Windows or WinComm PRO), you can simply put additional commands in a second command string; e.g., ATZ4 followed by ATS11=55.
• If you experience faxing problems, in addition to the other suggestions in this document (e.g., "What about third-party comm drivers for Windows?" and "Any other Windows tips?") you should make sure that you have firmware dated 4/18/95 or later. (For a firmware upgrade, call 3Com/USR at 847/982-5151.) Otherwise, it might help to initialize the modem with S36=0. If you are using Symantec WinFax, you might also try limiting your send and receive speeds to 9600 bps by adding the following to the [General] section of your WINFAX.INI file:

MaxTxSpeed=9600
MaxRxSpeed=9600
• With the Sportster (not the Courier), watch out for which profile you have set. If Y1 is set (which selects profile 1 rather than profile 0), and you do (say) ATS11=55&W, and then later use ATZ to initialize your modem, you won't get the S11 setting you saved! The reason is that &W always saves to the profile 0, while ATZ loads whatever profile Yn is set to, in this case profile 1.
• Options that are controlled by dipswitches are not saved in NVRAM (profiles 0 and 1). If you want them to be in a known state without worrying about the dipswitches, you should set them in your initialization string (e.g., E1Q0V1S0=0&C1&D2 for the default settings).
• An official table of Sportster models and firmware versions is available at "Sportster Supervisory Update Information".
• To obtain an SRO (Service Request Order) number for modem repair or upgrade, see "USRobotics on the Internet".

Where can I get information on my Rockwell-based modem?

• The best source for information is of course the modem manufacturer.
• Generic information is available from Rockwell International.
• See also "What are 'RPI' or 'WinRPI' modems?".

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