ftdi_latency_timer.md

FTDI latency timer (Windows only)

The default settings for FTDI serial devices mean terrible performance for OSBGET and OSBPUT, affecting *SPOOL*, *EXEC, *DUMP, and so on. The *CAT output speed is also slightly affected.

On OS X and Linux, the server can sort this out for you; on Windows, unfortunately, you need to do to it by hand. But it's easy enough, and it seems to be persistent:

1. Find device in Device Manager, somewhere in the Ports (COM & LPT) section)

2. Right click device and select Properties from the popup menu

3. In the properties dialog, select Port Settings tab and click Advanced... button

4. In the advanced settings dialog, find the Latency Timer (msec) option and set it to 1

5. Click OK and back out of all the dialogs

The default values for all the other options are fine.

Rebooting appears to be optional even if Windows tells you it's required.