Serial Cables Price Comparison
Compare 270 serial cables from StarTech.com, Lindy, DeLOCK and more — find the best price on RS232, RS422 and USB-to-serial adapters.
Serial Cables price comparison UK
Serial cables occupy a curious corner of the computer accessories market: overlooked by most consumers, yet absolutely indispensable for engineers, IT technicians, and anyone managing industrial equipment, PLCs, barcode scanners, or legacy hardware. Our catalogue covers 270 products, with prices ranging from 7 £ for a basic DB9 straight-through cable up to 7 £ for specialist RS-422/485 adapters from DeLOCK or Zebra. That spread tells you a lot about who actually buys these cables — and what they need them for.
StarTech.com dominates the listings with 28 products and a sensible average price, making it the go-to brand for most IT professionals. Their USB-to-serial adapter range is particularly strong: FTDI chipsets, COM port retention, and interchangeable DB9 screws/nuts are standard features across the line, which matters enormously when you're configuring network switches or programming industrial controllers. Kenable sits at the opposite end — budget-friendly cables averaging around 7 £, perfectly adequate for occasional use or simple RS232 connections where you're not pushing the limits of the standard.
The real split in this category is between passive serial cables (straight-through or null modem DB9/DB25 leads) and active USB-to-serial adapters. The former are cheap and simple; the latter require a conversion chipset, and the quality of that chip makes all the difference. FTDI-based adapters — as found across the StarTech.com and Lindy ranges — are the industry standard for a reason: rock-solid driver support on Windows, macOS, and Linux, with none of the compatibility headaches that plague cheaper Prolific or CH340-based alternatives. If you're buying for a professional environment, it's worth paying the premium. You can compare the full range of USB cables and signal cables alongside serial options to find the right solution for your setup.
DeLOCK commands the highest average price in the catalogue — their industrial-grade RS-422/485 converters and ruggedised adapters justify the cost in demanding environments. Zebra's serial cables, averaging around 7 £, are largely replacement accessories for their own barcode scanner and label printer ecosystem, so they're only relevant if you're already in that world. For general-purpose use, the sweet spot sits firmly between 7 £ and 7 £: that's where you'll find reliable FTDI-based USB adapters from StarTech.com, Lindy, and Digitus that will serve you for years without driver drama. Browse the broader KVM cables section if you're also managing remote server access alongside serial connectivity.
How to Choose the Right Serial Cable
Most people only search for a serial cable when something has stopped working — a legacy device won't connect, a PLC needs reprogramming, or a new laptop lacks a COM port. Getting the wrong cable wastes time and money. Here's what actually matters, based on the products we've analysed across this catalogue.
Connector type: DB9, DB25, or USB adapter?
This is the first question to answer. DB9 (9-pin D-Sub) is the most common RS232 connector on legacy equipment — routers, switches, industrial controllers, and older PCs. DB25 (25-pin) is rarer, mostly found on very old modems and some industrial gear. If your laptop or modern PC has no serial port at all (which is almost universal now), you need a USB-to-serial adapter cable rather than a straight serial lead. Don't confuse the two: a passive DB9 M/F extension cable won't help you if you have no serial port to plug it into.
FTDI vs. cheap chipsets — it genuinely matters
Active USB-to-serial adapters contain a conversion chip, and the choice of chip defines your experience. FTDI FT232 chipsets (used by StarTech.com, Lindy, and others in this catalogue) have native driver support in Windows 10/11, macOS, and most Linux distributions — plug in and it works. Cheaper alternatives using Prolific PL2303 or WinChip CH340 chips can cause COM port instability, driver conflicts on Windows updates, or outright failure on macOS. For one-off personal use, a budget CH340 cable might suffice. For anything professional or production-critical, insist on FTDI.
COM port retention for Windows environments
If your software (a terminal emulator, a PLC programming suite, or industrial SCADA software) is configured to communicate on a specific COM port number — say, COM3 — you need a cable that supports COM port retention. Without it, Windows may reassign the port number every time you unplug and reconnect, breaking your application's configuration. Most StarTech.com FTDI adapters in this catalogue include this feature; budget cables typically don't. It sounds like a minor detail until it costs you an hour of troubleshooting on a factory floor.
RS232 vs. RS422/RS485 — know your standard
RS232 is the default for most legacy IT equipment: point-to-point, up to roughly 15 metres, 115,200 baud maximum. It covers 90% of use cases. RS422 and RS485 are industrial standards designed for longer distances (up to 1,200 metres) and multi-drop networks — essential for building automation, industrial sensors, and some barcode scanner installations. The Equip USB-A to RS-422/485 adapter in this catalogue is one of the few options here for those protocols. Don't buy an RS232 cable hoping it will work with an RS485 device — they are electrically incompatible.
ESD protection level in industrial settings
In office environments, ESD (electrostatic discharge) protection is largely irrelevant. On a factory floor, near heavy machinery, or in any environment with significant electrical noise, it becomes critical. StarTech.com's premium adapter range specifies Level-4 ESD protection — the highest available — which protects both the adapter and the connected equipment from static discharge damage. If you're deploying cables in an industrial setting, this is worth paying for. The price difference between a basic adapter and a Level-4 ESD-protected one is modest compared to the cost of replacing a damaged PLC or scanner.
Cable length and signal integrity
RS232 is notoriously sensitive to cable length. The official limit is 15 metres, though in practice clean signals are achievable at longer distances with quality shielded cable and low baud rates. For USB-to-serial adapters, the USB portion can be extended with a powered USB hub, but the serial end should be kept short. The catalogue covers lengths from 30 cm to 10 m — for most bench or rack applications, 1–3 metres is the practical sweet spot. Longer runs in noisy environments should use RS485 rather than RS232.
- Basic and budget (From 7 £ to 7 £) : Passive straight-through or null modem DB9/DB25 cables from kenable, Nedis, and similar value brands. Fine for simple RS232 extensions or occasional use. No active chipset, no drivers required. Not suitable for USB conversion or industrial use.
- The reliable middle ground (From 7 £ to 7 £) : Where most USB-to-serial adapters from StarTech.com, Lindy, and Digitus sit. Expect FTDI chipsets, COM retention, and broad OS compatibility. This is the sweet spot for IT professionals and anyone connecting to legacy network equipment or serial consoles.
- Professional-grade adapters (From 7 £ to 7 £) : Ruggedised TPE construction, Level-4 ESD protection, and longer cable runs. StarTech.com's premium FTDI range and Lindy's more capable converters live here. Worth the step up for production environments or frequent field use.
- Specialist and industrial (Over 7 £) : RS-422/485 adapters, Zebra and Honeywell replacement cables, and DeLOCK's industrial-grade converters. Only relevant if you have a specific protocol requirement or are replacing OEM accessories for barcode/label printing systems. Overkill for general IT use.
Top products
- StarTech.com 3m Black Straight Through DB9 RS232 Serial Cable - M/F (StarTech.com) : The most affordable StarTech.com option in the catalogue and genuinely good value for a passive RS232 extension. Ideal for connecting a PC with a physical COM port to legacy equipment — but useless if you need USB conversion.
- StarTech.com 3ft (1m) USB to Serial Adapter Cable, COM Retention, Interchangeable Screws/Nuts, USB-A to DB9 RS232, FTDI IC, ESD Protection, Windows/macOS/Linux (StarTech.com) : The benchmark USB-to-serial adapter for most IT professionals: FTDI chipset, COM retention, ESD protection, and cross-platform drivers. The 1m length suits rack and bench work perfectly. Pay the premium — it's worth it.
- Equip USB-A to Serial RS-422/485 DB9 adapter cable (Equip) : One of the few RS-422/485 options in this catalogue, and the most widely available. Essential if your industrial equipment uses differential signalling — but completely unnecessary for standard RS232 applications. Don't buy this by mistake.
- StarTech.com 3ft (1m) USB to Null Modem Serial Adapter Cable, Interchangeable DB9 Screws/Nuts, COM Retention, USB-A to RS232, FTDI, Level-4 ESD Protection, Windows/macOS/ChromeOS/Linux - Rugged TPE Construction (StarTech.com) : The null modem variant for direct PC-to-PC or PC-to-device connections requiring crossed RX/TX lines. Level-4 ESD protection and TPE construction make this the right choice for field or industrial deployment. Overkill for a home office.
- Lindy USB to Serial Converter with COM Retention (Lindy) : A solid alternative to StarTech.com at a slightly lower price point. COM retention is included, and Lindy's build quality is consistently reliable. A good outsider pick if StarTech.com stock is limited or pricing spikes.
Related categories
Frequently Asked Questions
What is the difference between a serial cable and a USB-to-serial adapter?
A serial cable is a passive lead connecting two devices that both have physical serial (RS232) ports, while a USB-to-serial adapter contains an active conversion chip that creates a virtual COM port on a USB-equipped computer. If your PC or laptop has no DB9 port — which is the case for virtually all modern machines — you need an adapter, not a straight cable. The two are not interchangeable.
Is an FTDI chipset really worth the extra cost over a cheap CH340 adapter?
Yes, for anything beyond casual one-off use. FTDI chips have native driver support baked into Windows 10/11, macOS, and Linux kernels, meaning they work reliably across OS updates without driver conflicts. CH340 and some Prolific PL2303 adapters have a history of breaking after Windows updates or refusing to install cleanly on macOS. The price difference between a budget CH340 cable and a proper FTDI adapter is typically modest — well within the 7 £ to 7 £ range — and the reliability gain is significant.
What does COM port retention actually do, and do I need it?
COM port retention ensures that Windows assigns the same COM port number to your adapter every time you plug it in. Without it, Windows may assign COM3 one session and COM7 the next, which breaks any software configured to communicate on a specific port. You need it if you use terminal emulators, PLC programming software, or any industrial application that references a fixed COM port. For a one-time configuration task, it's less critical.
Can I use an RS232 serial cable with RS485 equipment?
No — RS232 and RS485 are electrically incompatible standards and cannot be used interchangeably. RS232 is a point-to-point standard with voltage levels between ±3V and ±15V, while RS485 uses differential signalling and supports multi-drop networks over much longer distances. Using the wrong cable will result in no communication at best, and potential damage to equipment at worst. If your device specifies RS485, you need a dedicated RS422/RS485 adapter such as the Equip USB-A to RS-422/485 in this catalogue.
What serial cable pitfalls should I avoid when buying online?
The biggest trap is buying a cheap USB-to-serial adapter without checking the chipset — many budget listings don't disclose whether they use FTDI, CH340, or a counterfeit chip, and counterfeit FTDI chips are a known problem on certain marketplaces. Stick to named brands (StarTech.com, Lindy, Digitus) that explicitly state FTDI in the product description. A second pitfall: confusing straight-through and null modem wiring. Connecting two PCs directly requires a null modem cable; connecting a PC to a peripheral (router, switch, PLC) typically requires a straight-through cable. Getting this wrong means no communication, and it's an easy mistake to make.
How long can an RS232 serial cable be before signal quality degrades?
The RS232 standard specifies a maximum of 15 metres (roughly 50 feet), though in practice reliable communication is possible at longer distances with low baud rates and quality shielded cable. At 9,600 baud with a well-shielded cable, runs of 30–50 metres are achievable in clean environments. In electrically noisy settings — factories, server rooms with heavy switching equipment — keep runs short or switch to RS485, which supports distances up to 1,200 metres by design.
Are serial cables still relevant in 2026?
Absolutely — serial interfaces remain the standard for configuring network equipment (routers, managed switches, firewalls all have console ports), programming industrial PLCs and controllers, and connecting barcode scanners and label printers in warehouse environments. The RS232 port may have vanished from consumer laptops, but the protocol itself is very much alive in professional and industrial settings. The demand for USB-to-serial adapters has actually grown as modern PCs dropped physical COM ports while legacy equipment remained in service.