UHF Multi Channel Transparent Data Link Transceiver
TDH2-433-9
 

The TDH2 is a 9600baud half-duplex multi channel OEM radio modem with a power output of 25mW. It is a 100% pin-compatible drop-in replacement for the Radiometrix TDL2A and can be used to replace the TDL2A in applications where greater radiated power is desired. TDH2 acts as a transparent serial cable to attached host. TDH2 is an intermediate level OEM radio modem which is in between a raw FM radio module like BiM2 and a sophisticated OEM radio modem like SPM2. It takes care of preamble, synchronisation, bit balancing and error checking along with automatic noise squelching.

Figure 1: TDH2-433-9 radio modem
Provided no two devices attempt to transmit simultaneously no further restrictions on data transmission need be made, as all transmit timing, valid data identification and datastream buffering is conducted by the unit. Synchronisation and framing words in the packet prevent the receiver outputting garbage in the absence of wanted RF signal or presence of interference. For multiple radio systems (polled networks) a TDH2 can be set to 1 of 8 unique addresses. As well as having unique addresses, the TDH2 allows operation on one of 5 pre-set frequencies in the 433MHz band. These frequencies are non-overlapping and simultaneous operation of TDH2s in the same area on different channels will be possible. Units are supplied on 433.925MHz (Ch0) as default.
 

Features

  • High quality, stable crystal reference
  • Low noise synthesiser / VCO
  • SAW front-end filter
  • Multi-stage ceramic IF filtering
  • Single conversion superhet
  • Serial modem baud rate at 9600bps (half-duplex)
  • Addressable point-to-point
  • 5 serial select wideband channels
  • Data Present indication
  • Fully screened. Low profile
  • Available as TDH2T transmitter and TDH2R receiver for one way communication
  • Conforms to Australian/New Zealand AS/NZS 4268:2003

Applications

  • Handheld terminals
  • EPOS equipment, barcode scanners
  • Data loggers
  • Industrial telemetry and telecommand
  • In-building environmental monitoring and control
  • High-end security and fire alarms
  • GPS systems
  • Vehicle data up/download

Technical Summary

  • Operating frequency: 433.925MHz (default)
  • Modulation: 16kbps bi-phase FSK
  • Supply: 5V at 50mA transmit, 22mA receive/idle
  • Transmit power: +14dBm (25mW)
  • Receiver sensitivity: -105dBm (for 1% data error)
  • 32 byte data buffer
  • Transmit power-up time: <4ms
  • Size: 37 x 26 x 8mm