I also use the updated WFW serial.386 driver from Microsoft WG1001.exe.
Note: there is only a small difference in throughput or cps (characters per second) between 57,600 and 38,400 baud settings on 14.4 modems.
Your mileage may vary!
I use comx as an example in this reference. Where x is the com port your modem is connected to, i.e., 1, 2, 3, 4. Example com2fifo=1
Windows for Workgroups and Cybercomm Driver Settings for Windows 3.1
In system.ini [*Windows for Workgroups (WFW) or cybercomm*] [boot] comm.drv=comm.drv [*WFW*] or comm.drv=cybercom.drv [*Cybercom and Windows 3.1*] [386Enh] comxfifo=1 [*Required Setting for 16550A UART*] comxbuffer=1024 [*Optional: 128 to 4096. Default is 128*] Correction: You do not need to make changes to the control panel or win.ini to change your baud rate for Trumpet.
Here are other setting you might try for WFW and a 16550A UART only. Information on these seetings is available from the Microsoft Knowledge Base Document: Windows Support of the 16550 UART
I do not use these settings.
[386Enh] comxrxtrigger=8 [*Optional WFW settings are 1, 4, 8, 14. Default 8*] comxtxfifo=0 [*Optional WFW settings are 0 or 1. Default 0*]