Modern experimental research often relies on the synchronization of different events prior to data analysis. One way of achieving synchronization involves marking distinct events with electrical pulses (event markers or “TTL pulses”), which are continuously recorded with research hardware, and can later be temporally aligned. Traditionally, this event marking was often performed using the parallel port in standard personal computers. However, the parallel port is disappearing from the landscape of computer hardware, being replaced by a serial (COM) port, namely the USB port. To find an adequate replacement for the parallel port, we evaluated four microcontroller units (MCUs) and the LabJack U3, an often-used USB data acquisition device, in terms of their latency and jitter for sending event markers in a simulated experiment on both Windows and Linux. Our results show that all four MCUs were comparable to the parallel port in terms of both latency and jitter, and consistently achieved latencies under 1 ms. With some caveats, the LabJack U3 can also achieve comparable latencies. In addition to the collected data, we share extensive documentation on how to build and use MCUs for event marking, including code examples. MCUs are a cost-effective, flexible, and performant replacement for the disappearing parallel port, enabling event marking and synchronization of data streams.

现代实验研究通常依赖于数据分析之前不同事件的同步。实现同步的一种方法是使用电脉冲（事件标记或“TTL 脉冲”）标记不同的事件，这些事件由研究硬件连续记录，并且可以在以后进行时间对齐。传统上，这种事件标记通常使用标准个人计算机中的并行端口来执行。然而，并行端口正在从计算机硬件中消失，取而代之的是串行 (COM) 端口，即 USB 端口。为了找到并行端口的适当替代品，我们评估了四个微控制器单元 (MCU) 和 LabJack U3，一种常用的 USB 数据采集设备，在 Windows 和 Linux 上的模拟实验中发送事件标记的延迟和抖动方面。我们的结果表明，所有四个 MCU 在延迟和抖动方面都与并行端口相当，并且始终实现低于 1 ms 的延迟。需要注意的是，LabJack U3 也可以实现相当的延迟。除了收集到的数据外，我们还分享了有关如何构建和使用 MCU 进行事件标记的大量文档，包括代码示例。MCU 是消失的并行端口的一种经济高效、灵活且高性能的替代品，支持事件标记和数据流同步。LabJack U3 也可以达到相当的延迟。除了收集到的数据外，我们还分享了有关如何构建和使用 MCU 进行事件标记的大量文档，包括代码示例。MCU 是消失的并行端口的一种经济高效、灵活且高性能的替代品，支持事件标记和数据流同步。LabJack U3 也可以达到相当的延迟。除了收集到的数据外，我们还分享了有关如何构建和使用 MCU 进行事件标记的大量文档，包括代码示例。MCU 是消失的并行端口的一种经济高效、灵活且高性能的替代品，支持事件标记和数据流同步。