I found one of these on my desk. I tried ports 1 and 4 and then ran out of things to plug in, but those two work fine. Are the entries in pucdata.c in some kind of order?
Index: pucdata.c =================================================================== RCS file: /cvs/src/sys/dev/pci/pucdata.c,v retrieving revision 1.104 diff -u -p -r1.104 pucdata.c --- pucdata.c 24 Apr 2016 06:47:56 -0000 1.104 +++ pucdata.c 5 May 2017 11:27:18 -0000 @@ -1421,6 +1421,19 @@ const struct puc_device_description puc_ }, }, + /* Moxa Technologies Co., Ltd. PCI I/O Card 4S RS232 */ + { /* "Moxa Technologies, SmartIO CP104EL/PCI" */ + { PCI_VENDOR_MOXA, PCI_PRODUCT_MOXA_CP104EL, 0, 0 }, + { 0xffff, 0xffff, 0, 0 }, + { + { PUC_COM_POW2(3), 0x18, 0x0000 }, + { PUC_COM_POW2(3), 0x18, 0x0008 }, + { PUC_COM_POW2(3), 0x18, 0x0010 }, + { PUC_COM_POW2(3), 0x18, 0x0018 }, + }, + }, + + /* Moxa Technologies Co., Ltd. PCI I/O Card 8S RS232 */ { /* "Moxa Technologies, Industio C168H" */ { PCI_VENDOR_MOXA, PCI_PRODUCT_MOXA_C168H, 0, 0 },