Messenger Systems - Messenger PSTN


  • Monitors 12 digital inputs (option for 24)
  • Built in PSTN modem
  • Forwards alarms to PC based Messenger Host Station and/or mobile phones
  • Makes programmable routine health check test calls
  • Fully reprogrammable over air and locally
  • Simple to install, no maintenance
  • Self contained lithium battery, no need to recharge, 10 year life
  • Main and standby contact numbers
  • Can automatically disable "fluttering" inputs
  • Wall mounting IP66/67  polycarbonate casing (UL94) - other options available on request
  • Test Button

For Application and Operation Refer toMessenger M61

To view a PDF of the Messenger PSTN Fact Sheet click on the link :: PSTN Messenger Fact Sheet

Technical Description

  • I/O - 24 Digital Inputs
  • Example Programmable Settings - Host Station number to forward alarms to Enabling/Disabling of inputs Software setting NO/NC for digital inputs Alarm Text Messages
  • Test Call (health check) frequency (default = 7 days)
  • Cable Entry. - 1 x 20mm cable gland allowing maximum cable diameter of 13mm
  • Maintenance Interval - 10 years (battery change)

Technical Specification


Standard Line Modem V22bis PSTN socket modem connection via RJ11 connector. Global PSTN approvals. On board stub antenna. Can be replaced by external antenna and lead.

PSTN Messenger


  • Inputs can be wired as either 24 x direct connections of which 12 may be opto isolated inputs
  • Type Normally Open / Closed is software selectable. Flutter suppression on individual inputs is software selectable if required
  • Minimum time required to detect input operation (i.e. debounce) 500 ms
  • Opto isolated inputs 5kV isolation across inputs, 24V nominal (80V-breakdown voltage between live and common)
  • Directly connected inputs Non-isolated, switched to zero volts
  • Input terminals High Density Connector. Maximum conductor size 24 awg On board
  • Event Logs Memory 100.

Power Supply

  • External Supply  - not required
  • Battery specification  - 36 Ah Double D Lithium 84w x 60h x 36d
  • Current consumption  - Quiescent: 10 micro Amps (nominal) TX/RX: 200mA to 600mA at 4V dc


  • Rating - IP67/66
  • Material - Non Flammable Polycarbonate, colour RAL 7035
  • Dimensions - 130mm (h) x 130mm (w) x 75mm (d)
  • Mounting - 4 x M4 (5mm diameter) wall mounting holes. Holes located outside watertight seal. Holes at 115mm vertical and horizontal centres
  • Standard Cable Entry -  1 x 20mm hole fitted with IP68 cable entry gland. Gland accepts cable diameters in range 4mm to 7mm


  • Approx. Weight (inc. modem and stub antenna) 0.7 Kg
  • Operational temp range 0C to +70C (PSTN Modem) - Industrial Option -40C to +70C, -45C to + 60C (Messenger unit)
  • Retry Algorithm (in case of failed calls/busy Host) 10 retries at approximately 1 minute intervals, followed by a 24 hour wait and then starts call attempts again
  • Health Check Test Frequency -1 to 99 days and option to disable


Independently approved  EN61010-1:2001   EN60068-2-1   EN60068-2-2  EN60068-2-3  EN61326:1997

The following are also available :: Messenger Configuration Kit      Messenger RSSI Measurement Kit      Messenger Training