High Speed Modems

High speed modems would include 9600 bps or higher modems and also 2400 bps modems with compression and error control protocols like MNP, V.42 and V.42bis.  Nowadays though we are talking about v.34 modems that run either 28.8k bps or 33.6 bps.  I like, use and recommend Supra Modems!  The modems have flashrom capabilities and may be updated by sending a program to the modem.  Supra was recently purchased by Diamond.  You can view the latest Supra info at http://www.supra.com

Maximizing the Efficiency

To get the most out of a high speed modem, you may need to change the configuration some from the factory settings.  Because the compression and error correction features can make the expected throughput somewhat variable, it is best to set the data rate between your Mac and the modem to a higher speed.  This is often called Òlocking the portÓ at a higher speed.  For 9600 bps to 14,400 modems, you would normally set the interface to either 19,200.  For Modems from 28,800 to 33,600 set your interface to 38,400.  If you have a special serial card or one of the AV Macs then 57,600 and above are possible.  In addition, you MUST use a ÒHardware HandshakingÓ cable so the Mac and the modem can handle the variable throughput.  All Macintosh models since the Mac Plus can take advantage of hardware handshaking.  The Mac 128, Mac 512K and Mac 512KE cannot use hardware handshake because the serial ports have only one of the two necessary control signals available.

If you have problems with your modem dropping carrier or hanging make sure you don't have the port speed set too high.  If there is line noise your term will appear to hang up and sometimes drop carrier.  Slow it down a notch and try again.

Modem Standards

V.32 is the CCITT (international) standard for modulation (the way a modem converts bits into sounds that can be carried by the voice telephone system) at 4800 and 9600 bps, full-duplex on voice-grade two-wire dial-up and leased telephone lines.  It was adopted in 1984.

V.32bis, which was adopted in early 1991, is 100% backward compatible with V.32.  In addition, it supports rates of 7200, 12000 and 14400 bps.  It also supports a Òrapid rate renegotiationÓ capability, which allows the modems to change speeds up or down in as little as 1/10th of a second, for example, to handle changes in line conditions (V.32 requires full retrain to change speeds, which can take 5 to 10 seconds).

V.34, adopted in 1994, is a modulation standard that supports speeds up to 33,600 bps.

V.42 is the CCITT standard for error control in modems.  It defines two protocols: the primary protocol, LAPM, on which all future extensions to the standard will be based, and an Alternative protocol, defined in an annex, which provides for backward compatibility with modems that implement MNP classes 2-4.  V.42 can be used with any full-duplex modem that uses async-to-sync conversion (e.g. V.22, V.22bis, V.26ter, V.32, V.32bis).

V.42bis is the CCITT standard for data compression in modems.  It is based on the Lempel-Ziv-Welch technique, with extensions from IBM, British Telecom, and Hayes, and can provide up to 4-to-1 compression on certain types of data.  It is currently standardized for use only in conjunction with v.42 LAPM.  V.42bis doesnÕt imply the implementation of any particular modulation scheme; specifically, you canÕt assume that a V.42bis modem also supports V.32 or V.32bis.

Optimizing Telefinder for Your Modem

 Open the TeleFinder User application from inside the TeleFinder/User folder. Notice that TeleFinder/User automatically opens the Default Settings file and loads the saved configuration. TeleFinder saves any configuration changes you make in whichever settings file is currently open. Use the ÒOpenÉÓ command from the File menu to choose a different settings file.  

Configure the TeleFinder/User with your logon name, password, BBS phone number, and information about your modem. 

1. Enter your logon name and password.
2. Choose a Connection Method
3. If you are supporting dial-in access through your modem then you will configure using the ÒModemÓ Connection Method.
4. Click in the ÒSetupÓ button in the Connection window. TeleFinder will open the ÒModem SetupÓ dialog.
5. Select the serial port your modem is connected to from the serial ports list of the ÒModem SetupÓ dialog.
6. Select a Modem Setup - The modem setup configures TeleFinder with settings to make your modem work properly. Scroll through the Modem Settings list, and click on the name that most closely matches the name of your modem to select it.

Notice that for some modems, there is a standard version and an ÒHHÓ version. ÒHHÓ stands for ÒHandshake HardwareÓ cable. Using a hardware handshake cable permits faster transfers with 9600 bps and faster modems.  You should try the ÒHHÓ settings first, and if you are unsuccessful in getting connections switch to the non ÒHHÓ settings. The cables that are shipped with high speed modems are generally hardware hand-shake cables. Unfortunately, there is no way of knowing, simply by looking at the cable, which type you have. Both the standard and ÒHHÓ cables have the same physical appearance.

7. Enter the Telephone Number of the BBS you want to connect to in the ÒTelephone NumberÓ text field. Note: If you need to dial Ò9Ó to get an outside line, enter it as Ò9,,Ó ( nine followed by two commas. When using calling cards, enter your calling card number in along with the telephone number. You may need to separate the telephone numbers from the calling card number with two or more commas. Each comma tells the modem to pause between the numbers.  Also you may need to disable call waiting.  If you have the call waiting service enter "*70,," (star seven zero followed by two commas) and then add the bbs number.

8. Click in the "OK" button to save the settings. Click in the Connect button to place the call.


TeleFinder dials the number using your modem and then waits for the BBS Server to answer your call. TeleFinder automatically will make repeated attempts to connect to a busy line. Click in the Cancel button to stop. You normally see the following messages in the Call Progress portion of the Connection window while TeleFinder is connecting.

       Opening the ConnectionÉ Connection EstablishedÉ

After the modems connect, TeleFinder logs you on to the bulletin board. This is when the bulletin board checks your name and password. The BBS starts this process. You should see these messages displayed in the dialer as log on takes place.

      Waiting for the hostÉ Sending name and passwordÉ Waiting for authorizationÉ Successful connection!Connecting to a TeleFinder BBS

NOTE: The logon procedure may ÒhangÓ at the ÒWaiting for the hostÓ stage if you choose the wrong settings. This happens if you select a hardware handshake setup and do not have the proper cable. Choose the standard setup if this occurs.

 If the log on fails, it is usually because the modems did not make a good connection. Poor connections often result from using the wrong settings. Correct TeleFinderÕs modem configuration if necessary. 

I highly recommend that you never set your modem port speed above 38,400.  You may want to try a faster setting like 57,600 if you have no retransmits during a file transfer.  Do keep in mind that just because you caught a clean phone line once you may not the next.  38,400 will give you fast reliable transfers on most modern computers with the new high speed modems.