radiometrix ltd tdm2 rf modem manual page 1 the tdm2 is a tdl2a radio module, combined with suitable interface circuits, power supplies and connectors, packaged in an attractive instrument case. in the simplest case, a pair of 'box modems' (with suitable aerials and power supplies connected, of course) can be connected directly to the serial ports of a pair of industrial pcs and the resulting wireless data link used without any further installation or programming. range of features rs232 driver and db9f connector for direct interface to pc serial port serial modem baud rate at 9600bps (half-duplex) addressable point-to-point 5 serial select wideband channels (in the 433.05 ? 434.79mhz european band) carries ascii and rtu modbus messages access to internal diagnostic/test modes using hyperterminal on board sma antenna connector signal led for visual indication of valid code received setup is simple as plug-and-play set-up and configuration using hyperterminal conforms to en 300 220-3 and en 301 489-3 size: 94 x 107 x 33mm (excluding connectors) applications handheld / portable terminals pdas, organisers & laptops industrial telemetry and telecommand in-building environmental monitoring and control remote data acquisition system, data logging fleet management, vehicle data acquisition uhf multi channel radio modem radiometrix hartcran house, 231 kenton lane, harrow, ha3 8rp, england issue 1, 21 may 2009 TDM2-433-9 n ew tel: +44 (0) 20 8909 9595, fax: +44 (0) 20 8909 2233 figure 1: TDM2-433-9 the tdm2 is a very simple 433mhz band radio data modem. it provides a medium ranged half duplex, transparent data link between a pai r of 9600 baud rs232 ports without any additional interface circuitry.
radiometrix ltd tdm2 rf modem manual page 2 12 4 3 on figure 2: tdm2 (rear view) looked at from the outside, the tdm2 presents : 9 way d-type rs232 port sma rf connector aerial 2.1mm power jack external power (9-15v) 4 way dip switch mode selection (see later) (all on the rear of the case) slide switch internal battery 'on/off' (in a recess, on the side of the case) three led indicators power on (green, on the left) valid data receiving (red, in the middle) transmitting (red, on the right) powering the tdm : the tdm2 radio modem requires a source of energy to operate. there are several options: 1. external supply . the tdm unit is intended to be supplied from a 9-15v dc supply (6-15v if the internal battery is not fitted). the basic unit requires up to 50ma, plus any extra current drain from the +5v output (pin 9 on the d-type). the supply can be fed in through the 2.1mm power jack (positive to centre connector) or through pin 1 of the 9 way d connector. 2. local +5v . the user may also power the unit by applying a regulated +5v supply to pin 9 of the d- type. in this mode of operation the internal battery must be removed, and switch 2 set to 'on'. the supply must be clean, and ripple free, as this mode of operation bypasses the internal supply regulator 3. there is provision for an internal pp3 battery . this is intended as a backup power source, and for use during experimentation and set-up. a standard, high capacity alkaline battery will provide around 15 hours of continuous operation. (the use of rechargable batteries in this unit is not recommended at this time) the internal battery is enabled by the recessed slide switch on the right of the case (slide switch backwards to enable the battery. to change the battery, the unit must be dis-assembled by removing the polymer 'feet' and removing the four assembly screws. the battery is retained to the pcb by a standard 'tie wrap'. when an external supply exceeding 9v is fed to the unit (through the power jack or the d connector), the internal battery is not used (there are steering diodes in series with both power sources) connecting the tdm : this unit is connected to an rs232 serial port via a standard 9 way d connector. true (bipolar) rs232 levels are provided by this interface. the interface provides txd/rxd, plus a basic cts function (indicating that the radio is busy receiving a data burst). other pins are used for functions specific to the tdm (mode and standby, power supplies).
radiometrix ltd tdm2 rf modem manual page 3 dtr pgm 0v txd nc cts rxd v cc frame ground +5v out 5 4 3 2 9 8 7 6 1 figure 3: tdm2 db9 serial port pin outs serial interface the tdm2 serial interface operates at 9600 baud only, with 1 start, 8 data and 1 or 2 stop bits pin name function 1 vcc raw supply voltage input (9-15v. ) 2 rxd rs232 data out 3 txd rs232 data in 4 dtr pull low to disable unit. (pin function enabled by switch 1) 5 0v supply ground 6 pgm pull low to enter program mode. (pin function enabled by switch 4) 7 n/c no connection 8 cts low = unit has valid data in rx buffer 9 +5v out regulated supply output. 200ma max. (independent of dtr switching) (pin function enabled by switch 2) notes : 1. pins 4 and 6 have internal pullups to +5v, pin 3 has a pulldown to 0v 2. all ' input' pins (3,4,6) will tolerate true +/- rs232 levels. no extra buffering is required. 3. the rx_busy (cts, pin 8) circuitry incorporates a pulse lengthening monostable, to eliminate the strobing or 'flashing' seen with tdl2a modules during streaming data, as the buffer fills and empties. 4. a simple addressing structure is included in the datastream. units may be programmed onto one of eight addresses (all units are supplied set to default addr=0) 5. a version is available in a robust extruded aluminium housing. contact radiometrix sales for details don't forget the aerial : the tdm2 is a wireless device, and will not function without a suitable aerial. the supplied part (a high quality 433mhz band helical type) is attached to the sma connector on the rear of the casing. use sufficient (but not excessive) torque to tighten the screw collar. finger- tight is correct. alternative aerials may be connected to this connector via a length of rf coax. contact technical support for advice. a good first demonstration can be had by: set up a pair of pcs, with serial (rs232) ports. connect them together with a null modem (pins 2/3 swap over) cable. run terminal emulator (ie: hyperterminal) programs on both computers. (port settings 9600 baud, 1+8+1, local echo) at this point you have a simple 'teletype' link between the machines. anything typed on one is seen on the other. now replace the null modem cable with a pair of tdm2 radio modems. you will see no change. the radio link seamlessly replaces the cable.
radiometrix ltd tdm2 rf modem manual page 4 configuring the interface : a 4 way dip switch is located in a recess on the rear of the case. as supplied, all switches are 'off' ('up'). these switches control certain interface functions: switches sw no. name function 1 dtr_en switch 'on' to enable pin 4 switching (otherwise unit is always on) 2 +5v/pin 9 switch 'on' to enable the +5v external supply pin 3 setup switch 'on' to force unit into setup/program mode 4 ext setup en switch 'on' to enable pin 6 (n_pgm) indicators : on the front of the hosing are three led indicators: 1) power : green, on the left. unit is powered when lit 2) transmit : red, in the centre when lit, the unit's transmitter is on, and it is sending a data packet 3) receive : red, on the right when lit, the unit has received a valid data packet, and is outputting it notes: 1) it ought to be emphasised that the tdm2 is a very simple, easy to use, device. it is also relatively unsophisticated. the data rate is limited to 9600 baud, the link is half duplex, and although there is a simple addressing structure, there is no provision for extensive data buffering, fec, or acknowledge/re-transmit error handling protocols. inside the box, the tdm2 is simply a tdl2a radio module with necessary interface circuits, power supplies and connectors. 2) the tdm2 provides a half duplex link: provided no two devices attempt to transmit at one time (a 'low' on rx_busy may be used as a primitive 'cts' indication) no further restrictions on data transmission need be made, as all transmit timing, valid data identification and datastream buffering is conducted by the unit. there is no 'transmit enable' pin. sync and framing words in the packet prevent the receiver outputting garbage in the absence of signal or presence of interference. 3) at the edge of it's range, or in the presence of other interferers, there will be packets (of 1-3 bytes each) lost, or occasionally corrupted. if a greater degree of data fidelity is needed, then the user ought to introduce another layer of data handling. in our own tests we have used the z- modem file transfer protocol with great success. in simpler, control type, applications these data errors will be of lesser significance.
radiometrix ltd tdm2 rf modem manual page 5 configuring the tdm2 in order to use all the functions embedded in the on board tdl2a modem, the user must be aware of the setup /programming facility, which allow different addresses and frequency channels to be set up, and if necessary accesses diagnostic test modes. as supplied, the tdm2 is set to address zero, and channel zero. to change these presets, it is necessary to enter setup/program mode. the tdm2 is programmed through the same rs232 port that is used for sending/receiving data. an rs232 terminal emulator (such as aterm or hyperterminal) is an ideal tool. to enter program mode either switch 3 is temporarily turned 'on', or pin 6 of the d connector is pulled low (providing switch 4 is 'on'). in this mode the radio link is disabled, but characters sent (at 9600 baud, as normal) to the unit are echoed back on the rxd pin. connect the tdm2 to the pc serial port using a serial straight through cable. the hyperterminal should be set with the following settings. 9600 baud rs232, 8 bit data, no parity, 1 start bit, 1 or 2 stop bits. no flow control. the unit will only respond to certain command strings: addr0 to addr7 these commands set up one of 8 unique addresses. a tdi2 will only communicate with a unit set to the same address. chan0 to chan4 these commands select one of 5 preset channels a tdm2 will only communicate with a another tdm2 set to the same address and the same channel. address and channel numbers are stored in volatile memory. on power-up the tdm2 reverts to the default in eeprom (as supplied this is always address 0 and channel 0) setprogram writes the current set address into eeprom as the new default. a tilda character (~, ascii 126dec) sent by the unit indicates end of eeprom write sequence following commands are normally only used for factory diagnostics: notone transmit unmodulated carrier lftone transmit carrier modulated with 8khz squarewave hftone transmit carrier modulated with 16khz squarewave # transmitter off a carriage return '' (00dhex) should be entered after each command sequence to execute it. releasing the 'setup' pin to high state (or turning off switch 3) returns the unit to normal operation
radiometrix ltd tdm2 rf modem manual page 6 condensed specifications frequency 433.925mhz ? chan0 (default channel) 433.285mhz ? chan1 433.605mhz ? chan2 434.245mhz ? chan3 434.565mhz ? chan4 frequency stability 10khz channel width 320khz number of channels 1 of 5, user programmed supply voltage current 6 ? 15v 30ma transmit 27ma receive/idle (plus up to 10ma in to rs232 port) 20ua disabled interfaces user power mode rf indicators 9pin d type 2.1mm connector 4 position dip switch sma power on (green led) sending (red led) receiving (red led) size 94 x 107 x 33 mm (excluding connectors) the case is an ergonomic abs moulding, designed by hcp a version is available in a robust extruded aluminium housing. contact radiometrix sales for details operating temperature -20 c to +70 c (storage -30 c to +70 c) spurious radiations compliant with etsi en 300 220-3 and en 301 489-3 transmitter output power 10dbm (10mw) 1db (a 25mw (+14dbm) power output aus/nz version is available) modulation type 16kbps bi-phase fsk fm peak deviation +/-25khz (nominal) adjacent channel tx power <-37dbm tx spurious <-45dbm receiver sensitivity -105dbm for 1% ber image -40db spurious / adjacent channel -60db blocking -80db nominal, 75db worst case lo re-radiation <-60dbm modem baud rate 9600baud (transparent, half duplex (a 4800 baud version, tdm2-433-4 , is available to special order) format 1 start, 8 data, 1 stop, no parity radio channel data rate 16kbps peak coding biphase packet length 3 bytes buffers 32 byte fifo flow control none (?rx busy? pin provided) addressing 1 of 8, user programmed data latency 14ms (first byte into tx, to first byte out of rx)
sales@radiometrix.com www.radiometrix.com radiometrix ltd hartcran house 231 kenton lane harrow, middlesex ha3 8rp england tel: +44 (0) 20 8909 9595 fax: +44 (0) 20 8909 2233 sales@radiometrix.com www.radiometrix.com copyright notice this product data sheet is the original work and copyrighted property of radiometrix ltd. reproduction in whole or in part must give clear acknowledgement to the copyright owner. limitation of liability the information furnished by radiometrix ltd is believed to be accurate and reliable. radiometrix ltd reserves the right to make changes or improvements in the design, specification or manufacture of its subassembly products without notice. radiometrix ltd does not assume any liability arising from the application or use of any product or circuit described herein, nor for any infringements of patents or other rights of third parties which may result from the use of its products. this data sheet neither states nor implies warranty of any kind, including fitness for any particular application. these radio devices may be subject to radio interference and may not function as intended if interference is present. we do not recommend their use for life critical applications. the intrastat commodity code for all our modules is: 8542 6000 r&tte directive after 7 april 2001 the manufacturer can only place finished product on the market under the provisions of the r&tte directive. equipment within the scope of the r&tte directive may demonstrate compliance to the essential requirements specified in article 3 of the directive, as appropriate to the particular equipment. further details are available on the office of communications (ofcom) web site: http://www.ofcom.org.uk/radiocomms/ifi/ information requests ofcom riverside house 2a southwark bridge road london se1 9ha tel: +44 (0)845 456 3000 or 020 7981 3040 fax: +44 (0)20 7783 4033 information.requests@ofcom.org.uk european radiocommunications office (ero) peblingehus nansensgade 19 dk 1366 copenhagen tel. +45 33896300 fax +45 33896330 ero@ero.dk www.ero.dk
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