How the indicator led tell you is ok or not

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

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?

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.

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?

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.

Is it possible to test db25 connections with this device? Maybe with an adapter,?

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.

Cablemax Cablemax Rs 232 Led Link Tester Db 9 Male | Desertcart British Virgin Islands

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Fully operational. Shipping worldwide, on schedule.Duty & taxes paid at delivery

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$55.37

Duties & taxes included

In stock

Sold byAmazon British Virgin IslandsDelivered byDesertcartCustomer service byDesertcartReturns14 days · 30 with PRO

Buyer Protection · Full refund if your order doesn't arrive as described.

Desertcart purchases this item on your behalf and handles shipping, customs, and support to British Virgin Islands.

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Description

🔍 Debug Like a Pro — Never Miss a Signal!

PLUG PLAY SIMPLICITY - No drivers or external power required—just connect and start troubleshooting immediately.
CROSS PLATFORM POWERHOUSE - Compatible with Windows 11 through 7, Linux, and macOS for versatile deployment across all your devices.
LIGHTNING FAST DIAGNOSTICS - Instantly verify RS-232 signal activity with intuitive dual-color LED indicators for each pin.
REAL TIME DATA FLOW MONITORING - LEDs flash to show transmit and receive data, giving you live status updates at a glance.
UNIVERSAL SERIAL COMPATIBILITY - Seamlessly works with any male or female 9-pin RS-232 serial connection, including DB-9 and DB-25.

The CABLEMAX RS-232 LED Link Tester is a compact, plug-and-play diagnostic tool designed for instant verification of serial COM port connections. Featuring dual-color LEDs for each pin, it provides real-time transmit and receive data monitoring without needing external power. Compatible with all 9-pin RS-232 serial devices and major operating systems, it’s the essential gadget for professionals who demand quick, reliable cable troubleshooting on the go.

Specifications

ASIN	B004OT995U
Best Sellers Rank	#34,833 in Computers ( See Top 100 in Computers ) #92 in Serial Adapters
Brand	CABLEMAX
Color	Black
Colour	Black
Compatible Devices	Personal computer, laptop, desktop
Compatible devices	Personal computer, laptop, desktop
Connector Type	DB-9
Connector type	DB-9
Customer Reviews	4.7 out of 5 stars 288 Reviews
Finish	Plastic
Item Dimensions	45 x 35 x 21 millimeters
Item Weight	1 Ounces
Item dimensions L x W x H	45 x 35 x 21 millimeters
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
Specific Uses For Product	Monitor
Specific uses for product	Monitor
UPC	729440626303
Unit Count	1 Count

Reviews

よ**ぎ

通信されているかどうかの確認のために購入しました。

シリアルのポートから先で通信できているかを確認するために購入したのですが、問題なく機能し、重宝しています。

9.06.2022

P**L

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.

24.02.2026

C**E

Mto bom

11.02.2025

M**I

I like it

Pretty good device and very good device for troubleshooting rs232 circuits

31.03.2018

J**M

Buen probador

Te brinda el estatus de cada señal

23.09.2019

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$55.37

Duties & taxes included

In stock

Sold byAmazon British Virgin IslandsDelivered byDesertcartCustomer service byDesertcartReturns14 days · 30 with PRO

Buyer Protection · Full refund if your order doesn't arrive as described.

Desertcart purchases this item on your behalf and handles shipping, customs, and support to British Virgin Islands.

Secure transaction

Trustpilot

TrustScore 4.5 | 7,300+ reviews

Abdullah B.

Great price for an authentic product. Fast international shipping too!

3 weeks ago

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Very impressed with the quality and fast delivery. Will shop here again.

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