Data Line Monitor model RS232LM


A basic tool for testing and troubleshooting V24/V28 and RS232C interfaces. Simply connect to a 9 or 25 way interface to see the state of every control and signal line

  • 24 red and 24 green high brightness LEDs, show line states at a glance
  • Four state monitoring of each line - red = SPACE/ON, green = MARK/OFF, both = clock or data, neither = no signal (-3V < Vs < +3V)
  • Face plate gives a complete description of all signals and explains the DB25/9 conversion
  • Connects to 25 or 9 way cables, using DB 25/9 mini adapters included
  • Can be used as a loop-back unit to test installed cables (requires breakout box / 5 volt source at other end of cable)
  • Ideal for field use - pocket size and supplied with carrying pouch, always ready - line powered so no battery to go fl at!


What's included  

Data line monitor RS232LM, two 9/25 way D-type mini adapters, carrying pouch, instruction booklet, 12 months warranty, lifetime support by phone or email

Order code:  RS232LM    We regret we can no longer supply this item  

Need something more comprehensive? Click here to learn about our RS232 breakout box
Abbreviated Specification & additional information
  • Monitors all active lines: 25 way = 1-6, 8-25, 9 way = 1-4, 6-9
  • Four state monitoring of each line: red = SPACE/ON (Vs > +3V), green = MARK/OFF (Vs < -3V), both = data or clock, neither = signal in transition region (-3V < Vs < +3V)
  • Interface connectors: One female BD25 type connector on the left hand hand side, one male DB 25 connector on the right hand side, either or both can be converted to 9 way using the adapters supplied
  • Power: line powered up typically 1mA @ 6.6 volt
  • Dimensions: (WxHxD) 130 x 56 x 20 mm (5.1 x 2.2 x 0.8 inches)
  • Weight: 102 g (3.3 oz)
  • Temperature: operating 0 to + 50 deg.C,   storage: -25 to + 70deg.C
  • RoHS compliant. CE marked, made in EU

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                       New Forest Electronics Tel. +44 (0) 1425 650089                 Issue 3.87    23rd April 2021