One User's Experience with 56k

The bad news is, my phone line at home doesn't support a digital connection. :-(

The good news is a 34kbps connection is much, much faster than a 14.4kbps one. :-)
I've also installed a SupraExpress 56Sp at a local store and get a consistent 44kbps connection, so I know the problem isn't the modem or ISP.

I did my first telecommunication between my Commodore 64 and a friend's Mac Plus at 300bps in 1986. In 1987, I worked for a retail computer shop that had 1200bps modems. We thought that was pretty hot, until 2400bps modems arrived. The industry stayed there for a while.

When I was working at ComputerLand, the organization standardized on a new NEC modem with 9600bps speed. We also had a pair of US Robotics 14.4 modems for communication between our two stores. That was cutting edge 5-7 years ago.

Several years ago, when the Supra 14.4 fax/modem dropped to around $100, I bought one for my Macintosh Centris 610. This would let me do remote access with our server at work. That modem served me faithfully until September 2, 1997, when it was unplugged to make room for my new 56k modem.

My ISP, Iserv, has elected to support the K56flex protocol, which eliminated the top-rated US Robotics Courier V.Everything as an option. Based on several years experience with Supra modems and very competitive pricing, I chose the Diamond Multimedia SupraExpress 56e. An added benefit was that the fax software would work with my current address book. Of course, following my own advice, I made sure it was software upgradeable.

Using the Modem

Iserv, my ISP, has a special phone line for testing K56flex modems. Unfortunately, they haven't got it fully configured yet, so speed is limited to what analog modems offer. However, my rep told me to just log on to the regular phone number -- a fair percentage of modems on the main bank have already been upgraded, although they are not publicizing this.

Over the past weekend, I managed to access a 56k modem every time I dialed in. Where the special phone line had yielded 24.0-26.4kbps connections, I am getting a consistent 34.0kbps. Compared with my old 14.4 modem, this is better than twice the performance I had at home. (Compared with the dedicated 56k line at work, it still seems slow.)

Of course, my setup isn't ideal. My antique Centris 610 has a slow 57.4kbps serial port and a 20 MHz CPU. On the other hand, I now have a connection faster than any 28.8 or 33.6 modem offers.

There are several factors I'll need to look into:

how clean a phone line do I have?
can I tweak the modem script?
how can I monitor connection speed on the fly?

I'll continue to update this page as I go along.

Update 12/19/97

I installed FreePPP on my Centris 610 earlier this week. One of the many options lets me set a higher serial port rate (DTE) than the 57.6 kbps default. The only drawback of FreePPP compared with Apple's PPP is that it doesn't show the modem's connection speed. So I have to assume the modem was connecting somewhere in the 31-34kbps range.

I tested the connection by downloading the statistics page from my ISP. This is a 3MB+ text file, so it is quite compressible. With the serial port clocked at 57.6 kbps, I managed a top throughput speed of 48.7kbps. Netscape reported an average throughput of about 5.5K.

Bumping the serial port to 115.2kbps made an immediate difference: top thoughput of 83.2kbps. Going the final step to 230.4kbps -- the speed of LocalTalk -- squeezed just a bit more performance from the modem, giving a top throughput of 88.4kbps with very few resent packets.

I also installed FreePPP on a Centris 660av this week, also using the Supra 56e modem. Results were similar to those at home: 49.2kbps throughput with a 57.6 kbps serial port setting, 81.6kbps at 115.2kbps, and 88.5kbps at 230.4kbps (again with few resent packets). Checking the PPP log, I noted that this machine typically has a 42-44kbps connection with Iserv.

Despite a slower reported modem connect speed at home (31-34kbps), actual throughput was comparable to to the faster 42-44kbps connection at the other site. Very impressive.

Of course, your results may vary depending on the DTE rate your computer is capable of, the modem you choose, the modem your ISP chooses, and your phone lines.

If you are using a Macintosh, please jump to my serial throughput page for more information.

UPDATE 1/26/98: I've been having some problems with my modem at home and one I installed at another location, mostly with failure to connect or dropping in the midst of a session. I made two discoveries:

Diamond was still shipping modems with old ROMs just a few months ago. Fortunately, their flash upgrade is simplicity itself.
Note that the following strings are for SupraExpress 56e and 56Sp on Macintosh only.
You really need to fiddle with modem strings -- don't trust defaults. Here are two that have worked reliably so far: "AT&FW2%E1%G0S95=45" and "AT&F1W2%E2" -- remember those are zeros.
A friend suggests "AT&F1Q0E0V1X4S95=1" -- I haven't tried it yet. He notes, "If this doesn't fix the connect problem, add an &J1 to the init string and see if it stabilizes the connection. Do not put an ATZ in the init string, as any other commands on the init line will be ignored. Supra has never been ATZ friendly...."

UPDATE 1/29/99: Things have improved since Iserv, my ISP, upgraded to v.90 modems. Until recently, my typical connection was 34kbps, but for the past few weeks, 44kbps has been the norm.

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