Portable computer designers made sacrifices as they continued to shrink the size of the systems through the 1980s. Internal expansion options were one of the first to be cut in the name of achieving a smaller form factor. For some systems, the only way to add a modem, for example, was to plug one into an external port.
External modems were almost as big as the portable computer in many cases, making them poor choices for traveling professionals. To solve that problem, some vendors shrank the modem as well.
The Touchbase Worldport modems were small and light enough to be easily carried in a briefcase or coat pocket. They had a DB25 connector for the computer and an RJ-11 jack for the phone. The Worldports (initially branded Worldlink) were compatible with the Bell 103/212A and CCITT V.21/V.22 telecommunications standards, which allowed them to be used worldwide. The Worldport 1200 was introduced in 1986, and the Worldport 2400 followed in 1987.
This type of battery-powered portable modem soon gave way to even smaller units based on the PCMCIA card standard.