InLine 79998 network cable tester for BNC RJ11 RJ45

The InLine Network Cable Tester 79998 is a passive tester for Ethernet LAN networks and telephone systems, designed to check the function, shielding and wiring of RJ45, RJ11, ISDN, UTP, STP and BNC cables. It operates from a 9V battery and features a compact white housing that is easy to handle. Coaxial cables are tested using a BNC adapter (50 Ω). Test results are indicated on a 9-LED bar, and the device supports both automatic and manual modes.

Advantages

The tester provides quick visual indication of line continuity and wiring faults via a 9-LED light bar. Its passive design makes it suitable for use without network power, and the ability to switch between automatic and manual modes adds flexibility for different testing situations. The compact form factor and standard connectors (BNC, RJ11, RJ45) simplify on-site testing of multiple cable types.

Suitable for (tasks / use cases)

• Checking wiring and continuity of RJ45 Ethernet cables
• Testing RJ11 telephone and ISDN cabling
• Verifying shielding and continuity of UTP and STP data cables
• Testing BNC coaxial connections with a 50 Ω adapter
• Quick on-site diagnostics for installation and maintenance

Key specifications

• Model: InLine 79998
• Supported connectors: BNC, RJ11, RJ45
• Power: 9 V battery
• Display: 9-LED light bar
• Modes: Automatic and manual
• Coaxial testing: requires BNC adapter (50 Ω)
• Colour: White

How to use

Connect one end of the cable to the tester’s main unit and the other end to the remote or adapter as required (for BNC use a 50 Ω adapter). Insert a 9 V battery, select automatic or manual mode, and observe the 9-LED light bar to identify continuity and wiring order. In manual mode, step through individual tests as needed to isolate faults.

Recommendations

Use the tester with cables disconnected from active network equipment to avoid false readings. For coaxial cables, ensure you use a 50 Ω BNC adapter. Replace the 9 V battery when indicator brightness or response becomes weak to maintain reliable results.