Cerial-X2
I now show three styles of a RS-232 PCB. Each one has TTL decoding and one type of UART. First one has a single 16550 (not shown) Second one has a choice of 16550 or 6551A but not both. Third one eliminates the patch area and includes a MAX232 type IC that would need to be hand-wired in. Hand-wired PCB, below. 2020/09/26 2020/09/29: Both UARTs now functioning on the hand-wired prototype PCB. 2020/10/22: A dual PCB, where both can function. 2020/11/16: Dual 1550's with full address selection. Second One. You choose which UART to install. Both are wired the same for the FTDI-232-5V connector. The double row of jumpers sets the address for each UART. Third One. 2020/09/26 Hand-wired decoding works. Bicycle spokes give support. Decoding TTL IC's are installed, but not in this pix. Top View, murdered Teensy PCB, added to a holey-pcb. Allows either 16550 or 6551A but not both. And not finished as yet, needs the FTDI connector, xtals, etc. Here it is with all parts stuffed (16550 an