Multidrop Modems

Westermo has multidrop modems both for private and for leased lines. Both type of modems can be connected to serial devices with RS-232 or RS-422/485 interfaces.

The V.23 standard which is the only multidrop leased line standard allows speed up to 1200 bit/s on two or four wire. Multidrop applications on private lines can have speeds up to 19 200 bit/s but the distances depend on the line quality and the number of drop points on the line.

Important for this kind of communication devices is that the units have good protection as the line interface is connected to long distance lines, exposed for all kind of external disturbances.

TD-23 V.23 Modem
  • Number of multidrop points, 16 (typical value)
  • 2-wire (half duplex), 4-wire (full duplex)
  • Transmission distance up to 25 km (15.5 miles)
  • Data rate 1200 bit/s (V.23)
TD-29 Modem
  • Transmission rate up to 19 200 bit/s
  • RS-232 and RS-422/485 interface
  • Data format up to 11 bits
  • Point to point or multidrop applications
TD-29P Profibus Modem
  • Allows PROFIBUS communication to remote applications
  • Half duplex communication on 9 600 bit/s and 19 200 bit/s
  • Dip switch configuration