--- product_id: 3958225 title: "RS-232 LED Link Signal Tester - DB-9 Male to DB-9 Female Connections for Serial Communication Monitoring" brand: "cablemax" price: "33377CFA" currency: XOF in_stock: true reviews_count: 13 category: "Cablemax" url: https://www.desertcart.sn/products/3958225-rs-232-led-link-signal-tester-db-9-male-to store_origin: SN region: Senegal --- # Instant dual-color LED diagnostics No external power needed Universal DB-9 RS-232 compatibility RS-232 LED Link Signal Tester - DB-9 Male to DB-9 Female Connections for Serial Communication Monitoring **Brand:** cablemax **Price:** 33377CFA **Availability:** ✅ In Stock ## Summary > 🔍 Debug Like a Pro — See Your Serial Signals in Real Time! ## Quick Answers - **What is this?** RS-232 LED Link Signal Tester - DB-9 Male to DB-9 Female Connections for Serial Communication Monitoring by cablemax - **How much does it cost?** 33377CFA with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.sn](https://www.desertcart.sn/products/3958225-rs-232-led-link-signal-tester-db-9-male-to) ## Best For - cablemax enthusiasts ## Why This Product - Trusted cablemax brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Cross-Platform Support:** Compatible with Windows 11/10/8/7, Linux, and macOS for versatile deployment in any professional setup. - • **Plug & Play Simplicity:** No drivers or setup required—just connect and start testing your serial connections immediately. - • **Power-Free Portability:** Operates without external power, making it the perfect tool for fieldwork and low-resource environments. - • **Instant Visual Diagnostics:** Dual-color LEDs flash to instantly reveal RS-232 signal activity and data flow direction, eliminating guesswork. - • **Universal DB-9 Compatibility:** Works seamlessly with any male or female 9-pin RS-232 serial ports across devices like PLCs, modems, and printers. ## Overview The CABLEMAX RS-232 LED Link Signal Tester is a compact, plug-and-play device designed for instant diagnostics of DB-9 serial connections. Featuring dual-color LEDs for real-time signal monitoring and data flow visualization, it requires no external power and supports universal RS-232 DB-9 male/female ports. Compatible across major operating systems, it’s an essential tool for professionals needing quick, reliable serial communication troubleshooting on the go. ## Description Product description RS-232 LED link Tester Introduction The DB9 Tester is the easiest way for you to test the connection on any male or female 9 Pin Serial connections. This adapter allows you to monitor the status of your connections by marking them with LEDS, which flash when there is activity on the pins. This device is easy to install, it features a Plug & Play Easy test RS-232 Host to Device link. Features Standard RS-232 DTE & DCE Interface with DB-9 / F & DB-9 / M Connectors. RS-232 DB-9 / DB25 Pin assignment No Power required. Easy to install , Plug & Play. Windows 11, 10, 8, 7, Linux, & macOS Data rate: Up to 200 Kbps Activity Monitoring LED Array Double color LEDs are implemented for an easy way to monitor the transferring & receiving of data. Pin Assignment Pin1 / Pin8 : DCD IN Pin2 / Pin3 : RXD IN Pin3 / Pin2 : TXD OUT Pin4 / Pin20 : DTR OUT Pin5 / Pin7 : GND Pin6 / Pin6 : DSR IN Pin7 / Pin4 : RTS OUT Pin8 / Pin5 : CTS IN Pin9 / Pin22 : RI IN Easily Portable With the tester's compact size along with an easy Plug & Play setup, quickly make sure your COM ports are working properly, effortlessly. Dimensions: 1.77 × 1.38 × 0.82 in. (L × W × H) Review: Absolute must have for communication debugging. - Works great for debugging PLC communication issues. I was chasing a ghost issue on an integrated PLC for a stationary battery backup system and this device showed exactly why the issue was happening. My com link cable had a broken wire at one end and this device instantly showed the result of it and finally put the ghost to rest after a quick cable swap. Review: DB 9 tester - Handy too. But couldn’t use. Need 25 pin connectors ## Features - [ Instant Diagnostics ] : Quickly test COM port function & verify RS-232 signal activity with dual-color LED indicators on each pin for easy troubleshooting. - [ Universal Compatibility ] : This serial tester works with any male or female 9-pin RS-232 serial connection, supporting DB-9 configurations. - [ No External Power Required ] : Operates without external power - ideal for field work, portable kits, or low-resource environments. - [ Plug & Play Installation ] : No drivers or setup needed - just connect and begin testing immediately. - [ Quick Status Monitoring ] : LED indicators flash to signal the direction of data flow, allowing easy real-time monitoring. - [ Broad OS Support ] : Compatible with Windows 11, 10, 8, 7, Linux, and macOS for flexible deployment across platforms. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B004OT995U | | Best Sellers Rank | #77 in Serial Adapters #6,731 in Computer Cables & Interconnects | | Brand | CABLEMAX | | Color | Black | | Compatible Devices | Devices with RS-232 DB9 female serial ports such as printers, modems, CNS machines, PLCs, radios, etc. Compatible Devices Devices with RS-232 DB9 female serial ports such as printers, modems, CNS machines, PLCs, radios, etc. See more | | Connector Type | DB-9 | | Customer Reviews | 4.6 out of 5 stars 303 Reviews | | Finish | Plastic | | Item Dimensions | 1.77 x 1.38 x 0.82 inches | | Item Weight | 1 Ounces | | Item dimensions L x W x H | 1.77 x 1.38 x 0.82 inches | | Manufacturer | Cablemax | | Mfr Part Number | DB9-TERS | | Model Number | DB9-TERS | | Number of Items | 1 | | Number of Ports | 1 | | Package Quantity | 1 | | Power Plug Type | No Plug | | Smart Home Compatibility | Not Smart Home Compatible | | Specific Uses For Product | Test the connection on male or female 9-Pin serial connections | | UPC | 729440626303 | | Unit Count | 1.0 Count | | Warranty Description | 1 Year | | Warranty Type | 1 Year | ## Product Details - **Color:** Black - **Connector Type:** DB-9 - **Item dimensions L x W x H:** 1.77 x 1.38 x 0.82 inches - **Specific Uses For Product:** Monitor ## Images ![RS-232 LED Link Signal Tester - DB-9 Male to DB-9 Female Connections for Serial Communication Monitoring - Image 1](https://m.media-amazon.com/images/I/61FCttfCyxL.jpg) ## Questions & Answers **Q: How the indicator led tell you is ok or not** A: Please use the following link, it has all the information on the operation, single page easy reference and description of the lamps and how the display of lit, not lit, and color of the LED is interpreted.http://serialstuff.amazonwebstore.com/CableMax-RS232-LED-link-Tester-DB9/M/B004OT995U.htm **Q: Are there simply LEDs connected to the lines, or does it have one shot circuitry to make the LEDs stay on for a bit even with a short pulse?** A: There is no one-shot dwell circuit, but the LEDs are two-color so you can see signal levels even when they're asserted false/space. **Q: Will this device show if the PC serial port is working properly, or does it have to be plugged in between the pc and a device, such as a printer?** A: it needs to be plugged in between the pc and a device. it will indicate comunication between the two on each of the pins of the rs-232. **Q: Is it possible to test db25 connections with this device? Maybe with an adapter,?** A: Yes, you will need a DB25 Male to DB9 female adapter. If you want to test online then you would also need a DB9 Male to a DB25 female adapter. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Absolute must have for communication debugging. *by P***L on February 24, 2026* Works great for debugging PLC communication issues. I was chasing a ghost issue on an integrated PLC for a stationary battery backup system and this device showed exactly why the issue was happening. My com link cable had a broken wire at one end and this device instantly showed the result of it and finally put the ghost to rest after a quick cable swap. ### ⭐⭐⭐⭐⭐ DB 9 tester *by R***H on March 3, 2026* Handy too. But couldn’t use. Need 25 pin connectors ### ⭐⭐⭐⭐⭐ Excellent - It does what it says it will do *by B***S on May 4, 2013* I like some other reviewers know for a fact that serial connectivity is not dead, finding a tester for DB-9 is not off-the shelf available for sure and finding this on Amazon was a blessing. I was in need of a test unit that was inline and simple to use and understand for checking signals from a control panel to an RS-232 external control port to mounted video projectors. I have to ascertain when a projector does not turn on or off from the wall controller if it is the wall controller / wiring, or the projector - if I call the wrong vendor responsible for warranty / repair I have to eat the service call cost. Having a small test unit with a visual indicator makes the diagnosis very simple. I did not find the LED indictors "dim" as some others have mentioned, mine were nice and bright, and exhibited no "bleed over" to the LED next to it. This unit is rugged and does what it says it will do, I did find like some other reviewers that the nuts next to one side of the connector get in the way when not mating to a cable but directly a device, simple to remove however and not a problem at all. I would recommend this to others. ## Frequently Bought Together - CABLEMAX RS-232 LED Link Tester DB-9 Male to DB-9 Female - RS232 Breakout Tester LED Monitor, DB9 Male to Female Breakout Module - DB9 null modem male to female slimline data transfer serial port adapter 2 Pack --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.sn/products/3958225-rs-232-led-link-signal-tester-db-9-male-to](https://www.desertcart.sn/products/3958225-rs-232-led-link-signal-tester-db-9-male-to) --- *Product available on Desertcart Senegal* *Store origin: SN* *Last updated: 2026-06-20*