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<b>Yet more on modem speed and spontaneous disconnects: PowerBook 3400 and beyond

Yet more on modem speed and spontaneous disconnects: PowerBook 3400 and beyond

We continue to get suggestions on how to deal with modem slow connection speeds and unexpected disconnects (as covered last time). While attention was focused on the PowerBook 3400 modem, some of these tips can apply to any modem user.

a. Follow-up to tips from last time For the PowerBook 3400 internal modem, several readers reported that shifting to the 3COM Impact Analog 14.4 script (as mentioned last time) resulted in a dramatic increase in the reported connection speed (to as high as 38,400 bps!). I tried this and found this to be so. However, my actual throughput did not seem any faster, so I am not sure how much to trust the speed, as posted by the OT/PPP control panel. I have since reverted back to the original internal modem script.

On the other hand, reader Gene reports that shifting to this script and adding the "?" command (as described on a MacFixIt Extras web page) did significantly increase throughput with no progressive slowdowns over time (I have not tried thisvariation yet).

b. Another script modification Peter Sichel (of Sustainable Softworks) writes: "I experienced a similar problem (of dropped connections) which I solved as described on my web page." The web page text reads in part: "I've noticed many of the CCL modem scripts supplied with OT/PPP were designed for ARA. Mine for example (Motorola Lifestyle/Power/Premier) assumes DTR will be used to disconnect the modem and return to command mode whereas OT/PPP appears to use this same signal for RTS flow control. The result was frequently dropped connections until I modified the CCL. To prevent data overrun to the Mac, these same ARA CCL scripts set the DTE rate to 57.6K which is less than optimal for a V.34 28.8K or faster modem." The web page provides details on how to modify these scripts. (Thanks also to Philippe Landau for noting this page.)

I am not sure Peter's suggestion is relevant to my problem, as I was having the same disconnects when using FreePPP. However, it seems worth a try for those willing to tackle the script editing task. More generally, several readers noted that Apple's unsupported utility, Modem Script Generator, can be used to create modem scripts; however, it cannot be used to modify existing ones.

Note: Peter Sichel is the author of two great utilities for Internet users: IPNetMonitor (a set of nine integrated Internet tools which allow Macintosh users to monitor their connection to the Internet; the tools are designed to help users quickly identify problems, locate where the problem is, and gather data which can be used to solve the problem) and OT Advanced Tuner (a simple control panel like application that allows you to view and set internal TCP/IP parameters including the TCP Window Size under Macintosh Open Transport).

c. Other suggestions

I installed AOL v.3's OpenOT extension and I have not had an unexpected disconnect since. (Peter Townes)

To avoid unusual disconnects with PPP, try adding S25=100 to modem string. It sets delay in lost signal before disconnect. Units are 100ths of a second. 255 is maximum. Default is usually at 25 and giving it a bit longer can help. (Jim Carr) [Note: I tried this and it seemed to have no effect for me.]