One User’s Experience with a 56k Modem

1997: The bad news is that my phone line at home doesn’t support a digital connection. :-(

The good news is that a 34 kbps connection is much, much faster than a 14.4 kbps one. :-)

I’ve also installed a SupraExpress 56Sp at a local store and get a consistent 44 kbps connection, so I know the problem isn’t the modem or the ISP.

I did my first telecommunication between my Commodore 64 and a friend’s Mac Plus at 300 bps in 1986. In 1987, I worked in a Heath/Zenith Computers and Electronics store that had 1200 bps modems. We thought that was pretty hot – until 2400 bps modems arrived. The industry stayed there for a while.

When I was working at ComputerLand, the organization standardized on a new NEC modem with 9600 bps 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 to 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 that the modem was software upgradeable.

Using the Modem

Iserv 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 to K56flex, 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 24.0-26.4 kbps connections, I am now getting a consistent 34.0 kbps. Compared with my old 14.4 modem, this is more than twice the performance I had at home. (Compared with the dedicated 56k ISDN line at work, it still seems slow.)

Of course, my setup isn’t ideal. My antique Centris 610 has a slow 57.4 kbps 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 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 is connecting somewhere in the 31-34 kbps range.

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

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

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

Despite a slower reported modem connection speed at home (31-34 kbps), actual throughput was comparable to the faster 42-44 kbps 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 1/26/1998

I’ve been having some problems with my modem at home and with one I installed at another location, mostly with failure to connect or dropping in the midst of a session. I made two discoveries:
  1. Diamond was still shipping modems with old ROMs just a few months ago. Fortunately, their flash upgrade is simplicity itself.
  2. Note that the following strings are for SupraExpress 56e and 56Sp on Macintosh only.
  3. You really need to fiddle with modem strings – don’t trust defaults. Here are two that have worked reliably so far (remember these are zeros, not the letter O):
    • AT&FW2%E1%G0S95=4
    • AT&F1W2%E2
  4. 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 1/29/1999

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

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