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DELOCK 86886: Null modem cable, 9-pin, male - female, mini connector, 0.5 m at reichelt elektronik
What is null modem? Null Modem cable vs Straight serial cable
Null Modem Cable F/F - D9 RS232 (2m) | The Pi Hut
Amazon.com: CableWholesale Null Modem Cable, DB9 Female to DB25 Male Serial Cable, UL Rated, 8 Conductor, Beige, DB9 Female to DB25 Male Serial Null Modem Cable, 6 Feet : Electronics
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Crossover or "Null Modem" vs. Straight Through Serial Cable - Decisive Tactics, Inc.