See the 902 - 928 MHz Transceiver constructed by Rick, VE3CVG, using the Linx HP II Modules.  There is lots of helpful information here, including notes on interfacing and control.  The  URL on Rick's web site is:  http://www.qsl.net/ve3cvg/900Linx/

 Bulletin - October 2001 -Linx announced that the HP II Series will be superceded by the HP 3 Series.  Shipments of HP 3 modules is to commence late in the first half of 2002.

  Please see the Linx Links page where you can access the detailed specifications for the HP modules.

    Transmitter and Receiver Modules
  The transmitters and receivers we are using are the Linx HP Series, the TXM-900-HP-II transmitter and the RXM-900-HP-II receiver.

  They have eight selectable synthesized frequencies, use FM/FSK modulation, and can be used for analogue (including audio from 50 Hz to 25 KHz) and digital data at rates up to 50Kbps.  Capability for both analogue and digital modes greatly increases the range of potential applications.

     Power amplifier 
  Linx has a power amplifier module (surface mount device) that will raise the transmitter output to 50 mW.  This is the BBA 519 A.

     Evaluation Kit
  Linx has available a Master Evaluation / Starter Kit, the MDEV-900-HP.
This kit has assembled circuit boards with prototyping areas on which you can do some testing of your interface circuits, and connections from the modules to RS-232 connectors for protocol development.  The kit includes two transmitters, two receivers and two antennas (rubber duck type).  The starter kit is priced at about $300US.  This makes it quite expensive in Canada.  In my opinion, especially for radio amateur use, the board designs have certain limitations.

     Do It Yourself
   You might be better to set up your own development assemblies if you want more flexibility, to work with different antennas, or if you do not need the RS-232 interface immediately.  You may want to have indicators showing when the transmitter is functioning, and when the receiver is receiving a useful signal, and other features not found on the Linx boards.  This could be as simple as a small PC board holding the receiver, one holding the transmitter, a clip for a 9 volt battery, a voltage regulator to 5 volts, and a plug-in prototyping board for testing your circuits.  The transmitter and receiver boards should have antenna connectors, and male headers paralleling the receiver or transmitter (these will be plugged in to female headers) to make connections easily to other circuits using push-on leads. 

   If you will be using a microcontroller, you might want to add a carrier board for it - such as the Parallax carrier board for the Basic Stamp II series of controllers.  Or you could build a Basic Stamp II from P.H. Anderson's kit.  HVW Technologies also has a kit for a Basic Stamp II assembly, the Stamp Stack II.  HVW has other controllers available.  See the Linx Links page.

   For suggestions on an approach for DIY Development, 
please see the Development file on this site.

    Hint
  If you can find it, have a look at the article in May 1998 QST magazine by John Hansen, W2FS, titled 'An Inexpensive, Remote-Base Station Controller Using the Basic Stamp'.  This discusses the control of an IC 706 transceiver with a remote 2 Meter handitalkie.  The circuit board for this project holds a Basic Stamp II module, a CM 8880 DTMF encoder/decoder, a 555 timer and two transistor switches.  This board is adaptable to many projects - with software modifications , of course.  

Circuit boards for this controller are available from Far Circuits.  FC can, I believe, supply a copy of the QST article.  Please see the Linx Links page.
    [More on this later.]