In most situations we would welcome a call from you so that we can have a more complete conversation about the application that you are currently evaluating however we understand that this is not always convenient so we have attempted to list a number of questions that from our experience have often arisen. If the question that you need the answer too is not listed then please do contact us when you are able to or mail us on firstname.lastname@example.org
Q: How do I reprogram the frequencies in my Solo, Duo or Trio talkback units?
A: These talkback units are reprogrammed using our Talkback GUI and the appropriate programming dongle cable. The latest version of the talkback GUI is v3.04.04 and is available to download from the Support pages on this website (after user registration).
These programming cables are available to buy:
SOLO programming dongle cable: 01136 1404 A
DUO programming dongle cable: 01136 1402 A
TRIO programming cable: 01136 1403 A
Note that these cables have active electronics in the connector shell. They are not just straight-through wired connections.
The SOLO, DUO and TRIO units can be reprogrammed to new frequencies within +/- 2MHz of the factory set frequencies. If an incorrect frequency is programmed, the LEDs on the top of the talkback unit will flash to indicate an ‘out of lock’ condition. You will need to reprogram the unit again with the correct frequencies
If the new required frequencies are more than +/-2MHz away from the original channel frequencies, please contact W&D tech support for advice. A factory retune may be possible.
Q: I am trying to reprogram my DUO and I cannot read back from it with an attached dongle cable.
A: You may experience difficulties reading back the channel information from an attached DUO if the DUO is within range of its Symphony talkback base unit or is picking up any other signal that is lifting the squelch on the DUO’s receive circuitry. Move to another location away from the Symphony base antenna.
Our programming dongles use the audio circuitry in the talkback units as an interface. In the DUO unit, it is important that the squelch is closed when attempting to reprogram it.
Q: What is an antenna ground plane?
A: The antenna system is crucial to getting the best performance from your radio devices. The antenna system is not just the antenna itself but also the coaxial cable and connectors. All parts need to be selected and installed correctly to achieve a good radio performance.
If you are using a simple rubberised whip or helical antenna, it is probably what is called a 1/4wave antenna. A common mistake made with these simple antennas is failing to provide an adequate metal ‘ground plane’.
For example, if you are using a short coaxial patch cable between your radio device and the antenna, you will probably need to provide a ground plane for the antenna to work. Without a metalised ground plane, these antennas cannot radiate their signals correctly and most of your transmit power is reflected back into the transmitter and wasted as dissipated heat.
The ground plane needs to be mechanically in contact with the outer shield of the coax. This is usually achieved by using a bulkhead antenna socket that screws down on to the ground plane.
A useful way of providing a ground plane for plastic enclosures is to use self-adhesive aluminium tape which is available for RS Components, Farnell etc.
Note: some larger antennas are ½ wave type. These do not need a ground plane. Feel free to ask W&D sales for advice.
Q: Aerials, antennas and antennae? What is the correct terminology?
A: Have a look on-line and you will see that there is considerable debate about the correct terminology, however it is generally accepted that an ‘Aerial’ is a receive-only device and that an ‘Antenna’ is for receiving and transmitting. For example, aerials are used for TV and Radio broadcast reception. For wireless voice, video and data systems, the term most often used is ‘Antenna’.
The correct plural of antenna is antennas.
Antennae are completely different...
Q: How many analogue Insight video links can be used on a small site?
A: Our analogue Insight video links are point-to-point line-of-sight wireless links. It has a direct feed from a PAL video camera. Maximum range is about 500metres and there are seven radio channels that can be selected.
Although there are seven selectable radio channels, it is not necessarily the case that seven links, each on one of the channels can easily be installed with good results. There is some overlap of radio signal into adjacent channels. Up to four analogue Insight links on a site can comfortably work, using channels 1,3,5 and 7.
A useful tip is to mix polarisation of the links. As standard the Insight antennas are set for vertical polarisation. By removing the brackets and reinstalling them 90° rotated, you get an antenna that has horizontal polarisation. There is very good isolation between vertical and horizontal radio waves. Simply changing polarisation like this can affect the signal strength by up to 100 times and this allows the possibility of using those extra skipped channels if more than four Insights are needed on a site.
Q: What are the main differences between Insight analogue and digital links?
- Our digital Insight links are bi-directional meaning that you can send PTZ commands to a camera as well as receiving digital quality video images.
- As analogue signals get weaker, the image on the screen gets noisy with lines and sparklies (random black & white dots). Digital video links maintain the quality of the image down to weaker signal levels and so longer point to point link distances are available with our digital Insight links – up to 2km.
- Our digital Insight links are encrypted preventing unauthorised receiving of the video signals. This may be important for certain end-users.
- It is possible to combine up to three camera video streams over a single digital Insight point to point link
- Digital Insight can be used as repeaters to enhance coverage range.
Summary: Analogue Insight is suitable for simple short-range static camera wireless links. Digital Insight is the choice for more challenging multi-camera systems using PTZ control and requiring wide-area coverage. Site surveys, system design and on-site commissioning help are part of the W&D offering.
Q: I need to link some on/off digital inputs wirelessly across a site. What W&D product should I look at?
A: If the distance is up to 500 metres or so, our 200T-DI and 200R-DO units are a good solution. These operate in the licence-free 173MHz VHF frequency band.
The 200T-DI is a battery-powered, completely sealed transmitter with two digital closing-contact inputs. These are suitable for monitoring alarms, level switches and other on/off devices. The built-in lithium battery has an expected 3-year life before needing replacement. Any detected changes on the digital inputs cause the transmitter to send a corresponding status update.
The 200R-DO is a companion VHF receiver with four relay contact digital outputs. These outputs can be mapped to up to three 200T-DI transmitters on your site and they will mimic any changes in the transmitters’ inputs that get signalled.
In addition to sending input change messages, status transmissions are also made by the 200T-DI every 15 or 60 minutes so that the 200D-DO receiver knows that the radio link is working okay and doesn’t need to alarm, which it can do if no transmissions are being received.
These 200T and 200R units have integral antennas and can easily be pole-mounted at a height to give extended range well over 1km in many environments.
Datasheets are available on this website. Please call or email the W&D sales department to discuss your particular application.
Q: How can I transfer meter pulses across a site to a central monitoring point?
A: Our 200T-DI and 200R-DO licence-free telemetry units have a pulse signalling mechanism. The battery-powered 200T-DI detects any change of state on its inputs (pulses >1sec duration). The number of ON to OFF transitions on input 1 is recorded as a total pulse count figure. This is part of the message that gets transmitted and picked up by the 200R-DO at the central ‘hub’ location.
At the central hub, the 200R-DO’s relay outputs are pulsed to match the same number of pulses reported by the 200T-DI transmitter. These relay contacts are wired to the central hub RTU.
This functionality gives a fast and economical solution to site-wide pulse count logging applications.
Q: How does the W&D 200T-RM differ from the 200T-DI?
A: Our 200T-DI has two digital inputs suitable for monitoring on/off switches and similar devices. The 200T-RM has a special electronic magnetic compass as part of its internal circuitry.This feature sees the 200T-RM most often used to detect and transmit confirmation of biological tank filter arm rotations in water treatment plants.
The sealed 200T-RM unit has an internal lithium battery that has a 3-year life. Every time a complete 360° rotation is detected, the 200T-RM transmits a pulse on its 173MHz licence-exempt frequency. If the hub receiver fails to pick up regular pulses it alarms to indicate a probable stuck filter arm.
The internal magnetic sensor can also be used to detect opening/closing of metal doors or access hatches without any direct physical connection, only proximity. The 200T-RM is installed close to the metal door or hatch and should it be opened, the detected magnetic field will change and a status update message transmitted.
Q: I am a first-time purchaser of radio modems. What accessories should I order to help me get started?
A: It is common for us to supply a pair of our ORION radio modems to first time users. ORIONs are shipped with an unsoldered DC power plug that the purchaser can solder wires to from a power supply. Soldering at this stage for a first timer user may not be convenient so we do have mains power supplies available to buy that have the connector already attached to the cable end.
In addition to power supplies, suitable antennas are required for the radio modems to function correctly. For short-range, proof-of-concept testing, we offer short rubberised antennas like you would see on a walkie-talkie. When directly connected to the antenna sockets on ORION modems, these simple antennas will give a typical system range of between 500 and 1000metres. For longer ranges we offer larger pole-mounted antennas with coaxial cable feeds for the ORION.
2 x ORION radio modems
2 x 12Vdc mains power supplies
2 x short flexible antennas
2 x Configuration cable (doubles as a serial data cable for connection to a DTE computer)
1 x CD with Configuration software program and user documentation
The above equipment is sufficient for a first time user to configure, test and put to use our ORION radio modems.
As you would expect, telephone and email technical support is available as needed.
Q. The ORION programming cable (01146 0202 A) has an RJ45 to DB9F adaptor. What wiring is inside it?
A. We use RJ45 connectors as readily-available compact interfaces with 8 pins each. A wiring diagram for the programming cable showing the Ethernet cable colours is given on page 33 of the ORION user manual (part no: 1892 1335). The RJ45 to DB9F adaptor allows us to build programming cables quickly in our factory.
Note that the ORION programming cable can be used for serial data connections to PCs. Connecting to other equipment may actually need fewer wires, for example many connections to RTUs etc. can be achieved with just three wires RXD, TXD and GND.
The RJ45 to DB9F adaptor, should you wish to use them rather than soldering a connector, is sold by RS Components (part: 818 700).
Q: I have just bought a couple of ORION radio modems and have not used them before. How do I easily configure them to work together?
A: You will have been supplied with an ORION programming cable. This looks like an Ethernet cable with an adaptor dongle at one end. It is actually a serial cable to connect the ORION to a PC or laptop running the ORION configuration GUI.
On your ORION there are two RJ45 connectors marked SERIAL B and SERIAL A
SERIAL B is the connector used for configuring an ORION radio unit using the software GUI.
SERIAL A is the connector for the serial data messaging that you want to send over the air (user data)
So you will use the SERIAL B socket to connect your ORION to your computer’s serial port.
Remember to power up the ORION. It needs a nominal 12volt supply (9 to 15v is okay). Centre pin is positive.
The GUI is an executable program. There is no installation to be done. Put the file on your Desktop or in a folder of your choice. When you start up the GUI it presents a list of all comm. ports that it detects on the computer.
Click the option button alongside the comm. port that is connected to your ORION. The GUI reads out of the ORION all of its parameters and presents them on the screen. These will be factory default parameters if this is the first time that these ORIONs are new. If you get an error message and you are using a USB to serial converter, please read the FAQ discussion on these devices.
The factory default settings will have a test radio frequency. If you have two new ORIONs, then the same test frequency will be in both. Unless you know that that particular radio channel is being used already at your location, there is no need to change it at this stage.
Make your serial data selection to suit your application.
Use the ‘Link’ menu item to write the changed parameters to the ORION. You will see confirmation in the left hand side window.
Press the DISC button to end the programming session with the attached ORION.
Repeat the process above with your second ORION.
You will now have two configured ORION serial data modems that will communicate with each other. There are several other parameters that can be adjusted if required once you have gained some experience with the units. The user manual gives comprehensive descriptions of all of the modes and parameters that feature in the ORION units.
Final reminder: SERIAL A is the connector to use for your serial data messaging
Q. What is the difference between full duplex, half duplex and simplex operation with radio modems.
A. It is useful to split this answer into two - an analysis of the actual serial data messages as if they were being sent on a cable and a separate look at the radio link and how it handles data messaging.
Serial data messaging, be it RS232, TTL-level, RS422 or RS485 can be one-way or bi-directional. An example of a one-way message is sending ‘On/Off’ commands from one place to another without any serial data response. Perhaps the messages are Lights-On and Lights-Off commands to a remote floodlight platform. No serial data response is needed as you will be able to see that the transmitted commands have been received. One-way serial data like this is called Simplex data.
Bi-directional serial data messaging is used where serial messages are sent and received from each end of the link e.g. requesting a remote telemetry unit for measured values. The request is in one direction and the response is in the opposite direction. This bi-directional data is Duplex data.
In a cabled system, one-way serial data is called Simplex data. Bi-directional data is Duplex data.
Next let’s look at the radio modem...
Radio channels are a scarce resource and need to be used sparingly. For this reason, the same radio frequency is generally used for transmitting and receiving, however not at the same time but sequentially – switching between transmitting and listening (receiving) as in walkie-talkie operation. While transmitting, no receiving is possible until the transmit button/line is released. This TX/RX switching is done automatically with radio data modems. Modern designs as used in Wood & Douglas’ radio modems have extremely fast TX/RX switching to give as close as possible a wireless –equivalent of a serial data cable.
If a radio link is used for one-way simplex serial data the radio link itself is said to be operating Simplex.
If a radio link is used for bi-directional duplex serial data the radio link itself is said to be operating half-duplex. Half-duplex indicates that the radios are switching between TX and RX even though they are handling full-duplex serial data.
Full-duplex radio links are available from Wood & Douglas to some licenced radio users who have particularly demanding data throughput requirements. Separate TX and RX frequencies (separated by several MHz) are used and the radio has full time TX and full time RX circuitry. Because of the scarcity of radio channels, these full-duplex radio channels are licenced by governments to users like utilities, military, police, broadcasters etc.
Full-duplex radios have TX and RX circuitry operating full time, not just switching between the two. It allows messages to be transmitted to another outstation B while simultaneously receiving from outstation A.
If in doubt what you need for your particular application, please call or email the sales team at Wood & Douglas for advice.
Q: USB to RS232 serial convertor problems. I cannot get your software to connect.
A: Nowadays it is getting very difficult to source a laptop or PC that has a good old-fashioned DB 9-pin serial commport. Computer manufacturers instead build their machines with USB sockets. There are hundreds if not thousands of after-market USB – RS232 serial convertors available and most will either have internal circuitry featuring a ‘Prolific’ chip or an ‘FTDI’ chip. These two chip manufacturers, Prolific and FTDI seem to dominate the market.
When you buy a USB to RS232 adaptor, you will be given some driver software with it. Because driver software needs to access the hardware cable it is given special privileges by the computer’s operating system (e.g. Microsoft) and needs to be stable and well written. Prolific driver software is not highly regarded judging by the myriad of adverse comments on internet tech forums. Some of our customers and here at Wood & Douglas too, have not had good results with USB to serial converters that have Prolific chips. Our strong recommendation is to buy adaptors that have FTDI chips inside. We have found these to work well with our software and radio units.
To find suppliers of suitable USB to RS232 converters, do an internet search for: - FTDI USB RS232
If you are lucky enough to have a working laptop with a hardware RS232 commport guard it carefully. Most electronics engineers endeavour to always have one of these old-style computers nearby. They remove any uncertainties when testing software serial connections and when USB to RS232 adaptors are being used. Software that works fine with the hardware port gives a proven reference point when selecting and testing for suitable USB converters.
Q: I have a PTZ camera control application. How can I configure and wire my ORIONs to work RS485.
A: Pelco-D is a common RS485 PTZ (Pan Tilt Zoom) protocol. Typically the signalling is 9600baud using a two-wire RS485 connection. Two-wire RS485 is a half duplex system. Actually this is of no consequence for most PTZ applications as the data flow is just one way, from controller to cameras. Control feedback is ‘seen’ as changes in the image on the CCTV screens.
Use the ORION configuration GUI to select the required baud rate and the RS485 serial driver.
The ORION connects to the camera or controller using just two wires from its Serial A connector. Cut a straight (not crossover) Ethernet cable in half and select the following two wires for your RS485 connections: -
White wire with brown stripe is the RS485 (A-) wire
White wire with blue stripe is the RS485 (B+) wire
Q: What is the difference between channel steps and channel bandwidth?
A: Let’s look at channel bandwidth first:
Wood & Douglas manufacture radio telemetry modules with 12.5kHz, 20kHz and 25kHz channel bandwidth. So what’s the difference? Well, consider first a radio transmission with no signalling on it – an unmodulated carrier. It occupies a very narrow bandwidth.
When our radio module transmitter is fed with a signal to transmit, the radio module frequency modulates the carrier spreading the energy over a very carefully defined bandwidth.
Channel bandwidth is set by the radio licencing authorities in your country and we have different build versions when we make the modules in our factory.
Wider bandwidths, if you are allowed to use them, are desirable if you want to squeeze more information across the radio channel. For example the W&D ORION radio modem can send 9600bps in a 12.5kHz radio channel. The 25kHz version has an over-air data rate of 19200bps!
Next we will look at channel steps:
Channel steps set the possible centre frequency increments. Typical numbers are 6.25kHz, 12.5kHz and 25kHz and are part of the factory build and configuration. In the diagram below, the channels can be programmed with 6.25kHz increments, e.g. 455.0000MHz, 455.00625MHz or in the case of the first channel shown, 455.01250MHz. The second channel has been programmed with a centre frequency of 455.04375MHz.
Sometimes the term channel raster is used to indicate programmable centre frequency step sizes.
When placing an order with us, we will ask you for your desired operating channel (centre) frequencies and the channel bandwidth. This is to ensure that we manufacture the correct version of our modules for your application.