Null modems. Laplink cables had DB-9 and DB-25 on both ends with the crossover built-in. There were some male to male cables that had crossover while others d

Null modems. Laplink cables had DB-9 and DB-25 on both ends with the crossover built-in. There were some male to male cables that had crossover while others didn’t. Then there were null modem adapter dongles for straight through cables. They were either male-female or male-male depending. Reminds me about older Ethernet: before Auto-MDI/MDIX on most NICs and switches, crossover RJ-45 cables were needed.