Pi Serial Modem Hat (RS232 9 Pin)

This Raspberry Pi Hat was designed for those who need a flexible serial UART connection with another device.  The male DB9 connector provides a full RS232 hardware interface just like older PCs used to. The jumpers allow various configurations without changing any other hardware.   Loopback (TX and RX connected together, so what is sent is automatically received) Null Modem (TX and RX swapped on the board. Useful for straight-through cables) Straight Through (This is useful when you have a null-modem cable) Handshaking CTS and RTS can be configured as straight through, or they can be swapped. Cable DCD, DTR,DSR, and RI can be connected in any configuration The hat comes with 11mm M2.5 standoffs, screws, and nuts.  Serial cables are available separately.