Premier Manufacturer
Reliable RS232 cable assemblies for industrial, automation, and legacy serial communication applications.
Romtronic manufactures custom RS232 cables with flexible configurations for DB9, DB15, DB25, DB37, HD50, and other serial connectors. With over 28 years of experience in wire harness and cable assembly production, we deliver high-quality, tested, and fully customizable solutions for OEMs and system integrators.
Our customised RS-232 cable assemblies
Our RS232 cable manufacturing process
Advantages of our customized RS232 cables
- Accept small-batch production orders at affordable prices.
- Equipped with multiple automated production equipment, high-end complex RS232 cable assemblies can be customized.
- Fast delivery: All processes, including welding, over-moulding, and performance testing, are conducted in-house, and orders are typically completed within 10-15 working days.
- A 100% product qualification rate, with all products thoroughly tested at 300% and having zero defects.
- We have obtained certifications such as UL, CE, and USB4TID, and we offer a range of options, lengths, and materials to meet your specific needs.
Engineering Assurance – Electrical Testing
Electrical testing is embedded into every Romtronic cable assembly program. From prototype to mass production, we apply structured electrical verification to ensure functional accuracy, electrical safety, and long-term reliability.
- 100% continuity and wiring validation
- Hi-pot and insulation resistance testing
- Resistance and voltage drop verification
- Custom functional electrical test development
Learn more about our Electrical Testing process
You may want to know more about RS232 cables
RS-232 interface form
RS-232 generally uses a 9-pin and 25-pin serial interface, divided into male (Male) and female (Female) connectors. There are two male connectors for DTE devices, one female connector for DCE devices, and different pins are assigned to other functions.
RS-232 (9-pin serial port pin definition)
| Number | Name | Abbreviation |
|---|---|---|
| 1 | Data Carrier Detect | DCD |
| 2 | Received Data | RxD |
| 3 | Transmitted Data | TxD |
| 4 | Data Terminal Ready | DTR |
| 5 | Ground | GND |
| 6 | Data Set Ready | DSR |
| 7 | Request To Send | RTS |
| 8 | Clear To Send | CTS |
| 9 | Ring Indicator | RI |
RS-232 (25-pin serial port pin definition)
| Number | Name | Abbreviation |
|---|---|---|
| 1 | Shield | / |
| 2 | Transmitted Data | TxD |
| 3 | Received Data | RxD |
| 4 | Request To Send | RTS |
| 5 | Clear To Send | CTS |
| 6 | DCE Ready/Data Set Ready | DSR |
| 7 | Signal ground/common return | SG |
| 8 | Received line signal detector | / |
| 9 | Reserved for data set testing | / |
| 10 | Reserved for data set testing | / |
| 11 | Unassigned | / |
| 12 | Secondary received line signal detector | / |
| 13 | Secondary Clear To Send | (S)CTS |
| 14 | Secondary Transmitted Data | (S)TxD |
| 15 | Transmission signal element timing | / |
| 16 | Secondary Received Data | (S)RxD |
| 17 | Receiver Signal Element Timing(DCE) | / |
| 18 | Local Loopback | |
| 19 | Secondary Request To Send | (S)RTS |
| 20 | DTE Ready/Data Terminal Ready | DTR |
| 21 | Remote Loopback/Signal Quality Detector | / |
| 22 | Ring Indicator | RI |
| 23 | Data Signal Rate Selector | / |
| 24 | Transmit signal element timing (DTE) | / |
| 25 | Test Mode | / |
Technical specifications of the RS232 interface
| Specifications | RS232 |
|---|---|
| Mode of operation | Single ended |
| Receiver Input Resistance | 3K to 7K Ohms |
| Driver load impedance | 3K to 7K Ohms |
| Receiver input sensitivity | +/-3V |
| Receiver input voltage range | +/-15V |
| Slew rate(max) | 30 V/µS |
| Max. driver current in high impedance state | +/-6mA at +/-2V |
| Max. driver output voltage | +/- 25 V |
| Maximum data rate | 460kbps |
| Maximum cable length | 50 feet |
| Number of drivers/receivers on one line | 1 driver, 1 receiver |
Advantages and Disadvantages of RS232 cable
Advantages of RS-232
- Widely used for point-to-point connections between DCE and DTE devices.
- Due to its simplicity, the RS-232 interface is supported in many devices.
- Low cost.
- No noise
Disadvantages of RS-232
- The interface requires a separate transceiver chip, which increases system cost.
- Used in single-master, single-slave configurations, not in single-master, multi-slave mode.
- Low bandwidth.
- Limited cable length.
- Increased power consumption.
Application of RS-232 cable
RS-232 cables are widely used for computer serial interface peripheral connections, such as connecting a computer to a printer or modem, and it is also used in industrial automation for connecting sensors and other devices to a control system.
Frequently Asked Questions (FAQs)
Q1: What types of RS232 cables do you offer?
We customize RS232 cables with DB9, DB25, RJ45, and other connector options, supporting straight-through or null-modem (crossover) wiring for industrial, communication, and legacy device applications.
Q2: Can you produce RS232 to USB or RS232 to TTL cables?
Yes. We provide hybrid RS232 cables such as RS232 to USB (with embedded converters) or RS232 to TTL/CMOS level adapters for embedded system integration.
Q3: Do you support custom pinouts and overmolded connectors?
Absolutely. We offer fully configurable pinouts, custom lengths, overmolded strain reliefs, and shielded cable options based on your specific requirements.
Q4: Are your RS232 cables suitable for industrial or rugged environments?
Yes. We offer durable cable constructions with reinforced jackets (PVC, PUR, TPE), EMI shielding, and ruggedized connectors for industrial use.
Q5: Do you provide testing or certifications for RS232 cables?
All cables undergo continuity and electrical testing before shipment. Upon request, we can provide inspection reports or testing data for quality assurance and documentation.
Get in Touch for Custom RS232 Cable Solutions
Romtronic manufactures custom RS232 cable assemblies for industrial equipment, embedded systems, automation controls, and legacy serial communication devices. We support a wide range of connector types (DB9, DB25, RJ45, and more), pin configurations, and shielding options tailored to your specific needs.
To request a quote, sample, or technical consultation, feel free to contact us through the form on this page or using the contact information below — our team will respond within 12 hours with expert assistance.
📧 Email: info@romtronic.com
📞 Phone: (+86) 199-2816-5824
Romtronic delivers reliable, high-quality RS232 cable solutions trusted by OEMs and system integrators worldwide.