Serial cables connect RS-232 devices such as computers, industrial equipment, controllers and network hardware that have a COM port. Our range includes over 250 cables with DB-9, DB-25 and DB-37 connectors in a variety of lengths. Delock, INLINE, Shiverpeaks, EFB-Elektronik and StarTech account for most of the models.
How to choose a serial cable
Connector type. DB-9 is the most common serial connector on computers and more recent devices, while DB-25 is more often found on older equipment, modems and printers. DB-37 is used less often, mainly in specialist industrial or telecoms hardware. All three appear in our range, so start by checking how many pins or holes the port on your device has.
Connector gender. A male connector has pins and a female connector has sockets, and only opposite genders mate. An extension cable needs a male end on one side and a female end on the other. Our range includes cables with a male first connector and others with a female one, and the second connector is mostly female, though some are male.
Straight-through or null modem. A straight-through cable wires each pin to the same pin at the other end, which suits connecting a computer to a modem or another peripheral. A null modem cable swaps the transmit and receive lines, so it connects two computers or two similar devices directly. If you are unsure, check the device manual, because the wrong wiring simply gives no communication.
Length. Our range includes cables of 1, 1.8, 2, 3, 5 and 10 m. RS-232 was not designed for long runs, particularly at higher speeds, so choose the shortest cable that reaches the device without strain.
Shielding. A shielded cable is less sensitive to electrical interference, which matters near motors, power cabling or other industrial equipment. On an office desk next to a computer, a standard cable is usually enough.
Brands we carry
- Delock: produces a large number of interface cables and adapters, including serial cables with DB-9 and DB-25 connectors.
- INLINE: a German manufacturer of computer cables and accessories, with many serial cables in its lineup.
- StarTech: known for connectivity products aimed at professional IT use, including cables, adapters and serial cards.
- EFB-Elektronik and Good Connections: German suppliers of cables and connectors used in offices and structured cabling.
- Lindy: a German company known for computer, video and audio connection cables.
Also in our range: Shiverpeaks, S-CONN maximum connectivity, Microconnect, Digitus, Tecline and Vivolink.
Frequently asked questions about serial cables
What is the difference between DB-9 and DB-25 cables?
The difference is the size of the connector and the number of pins: DB-9 has 9 and DB-25 has 25. DB-9 is typically found on computers and newer equipment, while DB-25 appears more often on older modems and similar hardware. Decide by looking at the port on your device rather than guessing which is more common.
Is a null modem cable the same as a normal serial cable?
No, the internal wiring is different. A normal cable connects each pin straight through, whereas a null modem cable swaps the transmit and receive lines. A null modem cable is meant for connecting two computers or similar devices directly to each other.
How long can a serial cable be?
The RS-232 standard is generally taken to work reliably up to roughly 15 m, although a good shielded cable at a lower speed can sometimes manage more. The higher the data rate, the shorter the cable should be. Our range includes cables from 1 to 10 m.
What if my computer has no serial port?
Many modern computers and laptops no longer have a COM port. In that case a USB to serial adapter can be used, with a standard serial cable connected to it. Before buying a cable, check the connector type and gender on your device or adapter.
