Breakout box RS232BOB
(Comtest 100C)


A comprehensive tool for testing and troubleshooting V24/V28 and RS232C interfaces. A bank of 25 switches allows any interface line to be opened or closed, the 100 LEDs show the state of the lines on both sides of the switches, any line can be patched to any other using the jumper leads supplied

  • 25 slide switches, to open or close any line
  • 100 LEDs to show line state on both sides of the switches
  • Four state monitoring of each line: red = SPACE/ON, green = MARK/OFF, both = clock or data, neither = no signal (-3V < Vs < +3V)
  • Patch any line to any other line using the jumper leads supplied (click for picture)
  • 2 LEDs for current loop measurement (4,10,20,60 mA)
  • Ground potential difference test capability
  • Two DB 25/9 mini adapters included, for connection to 25 or 9 way interfaces
  • Face plate gives a complete description of all signals and explains the DB25/9 conversion (click here)
  • Connector for external 9V battery included to allow cable testing or facilitate control line simulation
  • Can test any interface cable with DB25/9 connectors (requires external 9V battery)

(Click for larger picture)


RS232BOB(Comtest 100C) breakout box, two 9/25 way D-type mini adapters, 0.35 metre 25 way ribbon cable (terminated with one 25 male and one 25 way female DB25 connector), six 2 way jumper leads, two 4 way jumper leads, one PP3 battery lead, carrying pouch, instruction booklet, 12 months warranty, lifetime support by phone or email

Order code:  RS232BOB   We regret we can no longer supply this item  
Need something simpler? Click here to learn about our RS232 line monitor
Abbreviated Specification & additional information
  • Number of breakout switches: 25
  • Number of RS232 probe points: 50
  • Total number of LEDs: 102
  • Monitors all lines: 25 way = 1-25, 9 way = 1-9, on both sides of switches
  • Four state monitoring: 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 DB25 type connector on the left hand side, one male DB 25 connector on the right hand side, either or both can be converted to 9 way using the mini adapters supplied
  • Power: line powered, typically 1.2 mA per line (external battery required to allow cable testing or facilitate control line simulation)
  • Dimensions: (WxHxD) 188 x 85 x 20 mm (7.4 x 3.4 x 0.8 inches)
  • Weight: 280 g (8.9 oz)
  • Temperature: operating 0 to + 50 deg.C, storage: -25 to + 70deg.C
  • RoHS compliant, CE marked, made in EU
Jumper leads supplied

  • 6 two way jumper leads (16 cm / 6 inches long)

  • 2 four way jumper leads (i.e. four 1mm plugs daisy-chained)

  • 1 battery connector lead for optional use of external 9V battery


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