A: The pre-configured default is 19.2 kbit/sec, which was tested to work well even on the slowest systems (68000 CPU). We have successfully tested settings of 57.6 kbit/sec on Amiga 1200s (68020 CPU), and up to 115.2 kbit/sec on Amiga 3000 and 4000 systems (68030 and higher CPUs), using the standard Amiga serial port and the standard Amiga serial.device.
The performance of the Amiga serial port may be reduced depending on the resolution and depth of the frontmost screen. On older Amiga systems this begins to be noticeable when using Amiga screen modes having more than 8 colors. RTG (graphics card) modes have no negative impact on performance.
For better performance, the Buffer Size in the Amiga Serial Preferences should be set to at least 4096 bytes. Lower values can cause transmission problems at higher speeds, or, on 68000 Amiga computers and Workbench 1.2, even at the default speed.
Several replacements of the serial.device exist, which to different degrees claim and achieve a better overall system performance during use of the serial device. In general, it should however be considered that the Amiga does not allow for bi-directional transmission speeds higher than those which are possible with the serial.device. Some programs achieve higher transmission rates by taking over the system, or by sending data only (not receiving it). This is indeed possible, but Amiga Explorer is a system-compliant application, designed to multitask with other programs, and which needs both to to read and to send data.
Wireless links via Bluetooth serial adapters tend to be more reliable than null-modem cable connections at high speeds (but always within the limits of the Amiga CPU and serial port hardware).