Buy with Confidence: With Monoprice's Lifetime Warranty on all Cables, you can rest assured we stand behind our products and our customers. This cable features a female DE-9 (DB-9) socket on one end and a male DB-25 plug on the other. The 9 pins of the DE-9 connector are wired to 9 of the pins on the DB-25 connector While legacy PCs (post IBM PC/AT) typically use 9-pin RS-232 plugs external modems are usually equipped with 25-pin RS-232 sockets