Q: I have a domestic TV system being fed through a booster/splitter to four TV sets. I need to be able to view CCTV images on all of the TV sets and record to the VCR. I understand I can use the monitor-out from multiplexers, switcher etc directly into the scart socket of a TV or video. The pictures, however, would only be visible on the set I had it connected to. Is there any way to solve this problem?
A: Yes. You will need to purchase an RF Through Modulator. These devices turn the composite signal (the output signal from a multiplexer or camera) into an RF signal (the input signal used by TV tuners). Modulators can either be fixed or multi-channel; for your purpose I would recommend multi-channel. This will enable you to select a frequency signal away from those used by BBC, ITV, Sky etc. The modulator needs to be installed inline with the main aerial feed before the booster and video recorder.
Once fitted, tune all sets and video to the new modulator channel and away you go.
Sorting the LANS from the WANS
Q: More and more products within the CCTV industry now have the capability to be networked. From what I understand these products let you view cameras on designated networked computers, and remotely over a phone line. The more I have delved into this subject the more confused I get, so I have a couple of questions that I hope you can help with. Firstly, could you explain LANs, WANs and 10baseT etc. This may help solve my second question.
My customer does not have a network, however his digital recorder has a network port. He has asked what would be required to give him remote access i.e. a dial-in facility for accessing his pictures at home.
A: This is definitely the way manufactures have been heading for the past couple of years. Networking multiplexers, camera etc opens up an entirely new market. These systems let you expand the once ‘stand alone’ viewing stations, enabling them to distribute live and recorded images to PCs connected to a Local Area Network (LAN), Wide Area Network (WAN) and remotely. To cover your first question in its entirety would involve a few more pages than I’m allocated so I have compiled a quick reference guide that I hope will give you a fundamental understanding of networking and a base from which you can build.
You must have a modem
Now on to your second question. You cannot just stick a modem or a terminal adapter on to an Ethernet port. In order to remotely communicate with a networked device, whether it is a PC or a piece of CCTV equipment, you first have to create a network with a hub and modem. If this seems a bit daunting, don’t worry, help is at hand.
You can now purchase (from almost any PC outlet) a LAN modem.
A LAN modem is exactly what it says it is, a hub (usually four ports), giving you the facility to create a Local Area Network with either a PSTN modem or an ISDN terminal adapter, all built into one box.
Very little programming has to be done. However your first one could prove a little tricky. So have a good read of the manual before going to site. If you are still unsure, some manufacturers have web sites with good tech support sections. No doubt someone else out there will have experienced the same problem as you, so search the FAQs.
… And finally I would like to thank Dave Mulcahy for his kind comments about “Digital without the jargon” (Installer, October) and for pointing out that there are 540,000 recordable images on a standard three-hour tape, not 270,000 as I stated. Sorry, I had calculated the frames and forgot to double for fields.
Still, it is nice to know the articles are read in such depth!
* Send your questions to: Can we help?, Security Installer, The Builder Group, Exchange Tower, 2 Harbour Exchange Square, London E14 9GE.
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