inbellen

Inbellen is a Dutch term referring to dial-in access to a computer system or network via a telephone line and a modem. In this mode, the user’s modem dials the host’s telephone number and establishes a serial data link across the public switched telephone network (PSTN). Dial-in connections were common for remote login, file transfer, and early email before broadband became widespread.

Technically, inbellen relies on modems to convert digital data to analog signals and back. Data rates varied from 300 bits per second in the earliest systems up to tens of kilobits per second, with common speeds such as 1200, 2400, and 9600 baud, and later up to around 56 kilobits per second in suitable configurations. Protocols such as PPP or SLIP carried network traffic, while file transfers used XMODEM, YMODEM, or ZMODEM. Authentication was typically password-based.

Historically, inbellen played a central role in accessing mainframes, minicomputers, UNIX hosts, and bulletin board systems (BBS). Users employed terminal emulators to display remote screens and issue commands, often interacting with text-based interfaces via VT100-compatible terminals. The approach enabled remote work and information exchange long before internet services relied on always-on connections.

Decline and legacy: the rise of broadband, wireless access, VPNs, and cloud services led to the rapid obsolescence of dial-in. Today, inbellen remains relevant mainly for legacy systems, certain industrial or rural deployments, or for historical and educational purposes that illustrate early online networking.