Disadvantages of 56K

• Introduction

• Only one A/D conversion allowed

• 40 to 50K more likely

• 56K for downloads only

• 53K limit in the U.S.

• Requires digital lines at the ISP

• Won't work with some PBXes

Only one A/D conversion allowed

There's one requirement that will prevent some people from using 56K. For 56K to work, you can have at most one analog-to-digital conversion between your home or office and the Internet service provider (ISP). If there's more than one, you can't use 56K, and your connection will be limited to V.34 speeds (a maximum of 33.6K).

If your office is on a PBX, you may have problems getting speeds higher than 28.8 or 33.6K. See the PBX entry.

If your neighborhood's phone circuit has multiple A/D conversions, your only option is to move to another neighborhood. You're free to complain to the phone company, but don't get your hopes up.

The only 100% guaranteed test is to borrow a 56K modem and dial into your local ISP from your home or office. Be sure to install the drivers that come with the modem.

If you haven't tested the connection with a 56K modem, you should buy your modem from a dealer with a generous return policy.