It's DE9, Not DB9: A Tale of Misnamed Connectors
2025-07-26
For years, we've incorrectly called the 9-pin serial connector a DB9, but its correct name is DE9. This article explains the naming discrepancy. D-SUB connector naming follows a pattern: the first letter 'D' represents the D-shaped metal shield, the second letter specifies the shell size, and the following number indicates the pin count. DB denotes a 25-pin shell, while DE denotes a 9-pin shell. While DB9 has become the de facto name, it's technically wrong. SparkFun's new product uses the correct name, DE9, to correct this longstanding error and educate users on the proper technical terminology.