Serial and parallel adapters connect older equipment with an RS-232 or printer-style port to modern computers, such as point-of-sale systems, measuring instruments and network device consoles. Our range has over 40 products, including adapters, converters and connecting cables. The brands you will meet most often are EFB Elektronik, Datalogic, Zebra and HP.
How to choose a serial or parallel adapter
Standard. RS-232 is the most widespread serial standard, while RS-422 and RS-485 are mainly used in industry and over longer distances. They are not interchangeable, so check what your device's documentation specifies first. A parallel port is needed mostly for older printers and some programmers.
Connector type and gender. Serial devices usually have a DB9 connector, older ones may use DB25, and parallel ports use DB25 or Centronics. Check whether you need a plug or a socket, because two connectors of the same type will not mate. Some devices need a crossover (null modem) cable rather than a straight-through one.
Chipset and drivers. How well a USB adapter works depends largely on its chipset, for example FTDI or Prolific. Before buying, make sure the manufacturer lists drivers for your operating system: Windows 11, Linux or macOS.
Number of ports. One adapter is enough for a single device. If you need to connect several, choose a multi-port model, and for a desktop PC a PCI Express expansion card is sometimes the more practical option.
Length and protection. A short adapter plugs straight into the computer, while a longer cable is needed when the device sits further away. In industrial settings, look for galvanic isolation or surge protection.
Brands in our range
- EFB Elektronik: a German company known for connecting cables and adapters for offices and data centres, and the brand with the most products in this category.
- Datalogic and Zebra: makers of barcode scanners and mobile data capture devices, so their cables and adapters are generally meant for connecting those devices to checkout or warehouse systems.
- Exsys: specialises in serial and I/O expansion cards and USB adapters.
- Axagon: a Czech manufacturer known for USB adapters and computer accessories.
- Digitus: the ASSMANN Electronic brand, built around network and connecting cables.
Also in our range: HP, Micro Connect, Value, Good Connections, Fujitsu and Artdev.
Frequently asked questions
What is a USB to RS-232 adapter used for?
It is used when a computer has no serial port but a device such as a cash register, scales or a network device console requires one. The adapter creates a virtual COM port on the computer. Most modern laptops have no built-in serial port.
Will an RS-232 adapter work with an RS-485 device?
Generally not. RS-232 and RS-485 use different signal levels and wiring, so an RS-485 device needs a matching RS-485 adapter or converter. Check the device's specification before you buy.
What is the difference between serial and parallel ports?
A serial port sends data one bit at a time over a single line, while a parallel port sends several bits at once over multiple lines. Parallel ports were common on older printers, while serial ports are still used in industry, point-of-sale systems and measuring equipment.
Can I connect an old printer through a USB to parallel adapter?
Usually yes, because these adapters are designed mainly for printers. They may not work with devices that need direct access to the parallel port, such as some programmers or security dongles. Check the manufacturer's compatibility notes first.
