Multi-Port serial cards, such as the BocaBoard, are all but dead. If you are in business as an Internet Service Provider (ISP), you will not want to use any of these devices, because the new 56k modem standards will not support them. Instead, you need digital modem/terminal server combinations such as the Livingston PM3 ™ , Cisco 5200 ™ or US Robotics Total Control ™. Otherwise, you simply won't be competitive in major markets. Users want high speeds; you won't be able to provide them with a BocaBoard or other multi-port serial card.
Even as a multi-port serial card, the BocaBoard is hopelessly obsolete. The overwhelming majority of people who want to buy a BocaBoard would be better off getting a accelerated card such as the Cyclades™ or Rocketport™. (When last I looked, Rocketport™ was a better board, but Cyclades™ had the most stable kernel support). Accelerated cards use less of the CPU of your machine, and so you can support more ports per computer with less performance degradation.
That being said, perhaps you own one of these devices and want to make use of it, or perhaps you are planning an ISP based on a low-cost business model that basically means the use of cast-off equipment from others. In that case, the information in this document should be useful for you. But again, I repeat: The person who buys a new BocaBoard at this point probably needs a few more clues before starting his ISP or other venture.