The new Intelimax+ MA-2020 modem features the ability to be configured as either a RS-232 or RS-485 half or full (RS-422) duplex interface, via its advanced software. This feature provides the ability to use the Intelimax+ for point-to-point or multi-drop (daisy-chain) scenarios giving users additional flexibility to simultaneously connect to a wider range of hardware and perhaps more importantly, saving time and costs.

Our new Intelimax Lite MA-2060 serial modem comes standard with an RS-232 interface, however the option of a RS-485 interface is available via a hardware configuration.

Where is RS-232 and RS-485 used?

RS-232 is one of the most widely used standards for serial data communications as a result of it being simple and reliable in low data rate scenarios. Typical applications include connections to computer peripherals, industrial controller, and modems. RS-485 is preferable if the equipment is used in electronically noisy environments such as factories, utilities sites or substations, or if a multi-drop setup is required and supported by the equipment. Device addressing and multi-talk control needs to be considered and is usually supported by the software protocol being used between the communicating end devices.

RS-485 is used in a wide range of IT and M2M applications including aircraft, electricity metering, and industrial control. Many open and proprietary control system protocols such as Modbus and Profibus utilise RS-485 as a physical layer because of its resistance to electrical noise. RS-485 is also useful in HVAC, building automation and parking systems due to its use of simple wiring and ability to operate over very long cable lengths.
RS-232 vs RS-485. What’s the difference? 
Both RS-232 and RS-485 are standards for serial communications for the transmission of data. RS-232 was first introduced and standardised by EIA in 1962 with the most recent revision F coming in 1997. RS-485 came later, being introduced in 1983 with the most up to date revision in 2003. 

RS-232 is a communications interface for connecting modems and control equipment to computers or servers. RS-232 is single-ended with communication being made between a DTE (Data Terminating Equipment) such as a computer and a DCE (Data Circuit-Terminating Equipment), such as a modem.
  • Point to point serial communications
  • Generally RS-232 is limited to transmission distances of 15 meters and a data rate up to 115.2kbits/s
  • Uses voltage levels of between +3 and +25 V to indicate a logic 0, or between -3 and -25 V to indicate a logic 0. The transmitter and receiver a single-ended with a ground reference rather than differential.

RS-485 is a standard interface for not only a single device-to-device interface but also a communications bus that can be used to form simple networks of multiple devices. Its configuration and specifications also extend the range and data rate beyond the RS-232 interface capabilities.
RS-485 can operate in either half or full duplex configuration. When operating in full duplex (interoperable with RS-422) additional transmit and receive lines are used.

RS-485 allows high data rates communications over long distances in environments where is often electronically noisy such as utility sites and substations. According to the standard, 100kbit/s is the maximum speed over a distance up to 4000 feet (1200 meters) can be achieved.
  • Uses differential signalling on two lines, a logic 1 is a level greater than -200 mV and a logic 0 is a level greater than +200 mV.
  • Standard specifies 32 drivers and 32 receivers, if using RS485 full duplex (RS422) then the maximum is 1 driver and up to 10 receivers.
  • RS-485 allows for a transmission distance of up to 1200 meters.
Other Maxon Devices that support RS-232 and RS-485
The Smartmax MA-2010 Supports RS-232 and RS-485 full duplex. Smartmax is a unique and intelligent fusion of 3G capabilities with advanced functionality of a modem/router, complete with built-in DNP3; all encased in a durable & robust metal casing.

Multimax MA-2040 (3G or 4G) supports RS-232 and RS-485 half duplex. With multiple connectivity options, the Multimax MA-2040 is a rugged router suitable for a diverse range of industrial M2M applications. The Multimax features dual-SIM capabilities as well two Ethernet ports, which provides advanced redundancy functionality.