Pinouts for built-it-yourself adapters:
RJ45-DB25F (standard)
RJ45F DB25F
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NC 1 22 RI
DSR 2 5,6,8 CTS,DSR,CD
DTR 3 20 DTR
SG 4 7 SG
RD 5 3 RD
TD 6 2 TD
RTS 7 unused
NC 8 unused
RJ45-DB9F (somewhat more convenient)
RJ45F DB9F
==== =====
NC 1 9 RI
DSR 2 1,6,8 CD,DSR,CTS
DTR 3 4 DTR
SG 4 5 SG
RD 5 2 RD
TD 6 3 TD
RTS 7 unused
NC 8 unused