 |
|
SmartCable |
|
|
The SmartCable is the main control interface between the computer, camcorder and VCR. It gets the accolade 'Smart' because it contains an element of electronic circuitry within the assembly, but there are no logical or control processes involved. This aspect is handled by the computer. There are 3 varieties of SmartCable currently in use, each having unique interface characteristics. By far the most popular and complex is cable 006, which is the version that will be described here. This cable has its origins in the days of Windows 3.x, when direct, real-time program access to serial port lines was relatively easy, through the 16-bit operating system. With the introduction of Windows 9x (32-bit OS), this direct access was denied to programmers, without writing complex drivers (a task not to be undertaken lightly). You see, the SmartCable uses the ports in an unconventional manner, quite different from the normal Serial/Modem use they were designed for. Pinnacle must have had to 'jump through hoops' to get this original cable to perform its Studio400 role, using the later operating system, since the ports were now treated as buffered file streams. This could well be the reason why a number of users had trouble interfacing the cable to their computers. It may also explain one of the reasons why the earlier Studio200 had a better reputation for cutting accuracy over its successor. It is unlikely that, if Studio400 were being developed today, the serial com ports would have been used in quite the same way (if at all). The circuitry is contained within the Infra-Red Module, and performs the following functions.
The module operates from internal ±12v power rails, using a 'phantom power' technique - using a pair of the signal lines to charge reservoir capacitors (via diodes) to their quiescent voltage levels (+ or - 12v). This is necessary because power is not directly available from the PC at the com port sockets. Only a low level of power is available using this method, but it's within the demands of the SmartCable circuitry. If I can obtain permission from Pinnacle Systems to publish the full circuit diagram of the module, I shall add it to this page at a later date. It is an interesting circuit to analyse, particularly since it has a couple of design flaws (not, I believe, Pinnacle's fault), one of which is the tendency to crash the computer if an attempt is made to detect the SmartCable without the LANC jack plugged into the camcorder. I have a fix for this, but it will have to wait until another day......
|
|
How to add Ctrl-S capability to SmartCable 006SmartCable 006 provides Infra-Red, Sony LANC, or Panasonic Ctrl-M control of the camcorder, and Infra-Red control of the VCR. For more reliable control of VCRs equipped with Sony Ctrl-S ports, an additional cable (004) was available that replaced the IR control with a hard-wired Ctrl-S connection. This cable, although readily available in the USA, has been difficult to obtain in many countries, and has been fairly expensive. We now understand that Pinnacle have depleted their stocks of this cable, and do not plan to manufacture any more, so even US customers are going to find difficulty in the future. Fortunately, all is not lost, because I am now going to describe a modification to cable 006, that provides a Ctrl-S output, in addition to its normal 006 function. All you need is a little electronics knowledge, or know someone willing to do the modification for you. Please note that permission has been obtained from Pinnacle Systems to show details of the SmartCable assembly and circuit board, and to describe this modification. Pinnacle Systems however, take no responsibility for the performance of this modification, or any damage that may result from attempting the modification. This is solely the responsibility and judgment of each individual user.
|
|
How It WorksIn common with most other manufacturers, Sony send a serial data control word (known as a 'baseband' signal) from their remote controls, superimposed on a high frequency carrier, and emitted from an Infra-Red (IR) transmitter. The VCR picks up the IR transmission, extracts the baseband signal from the carrier, and passes the serial data control word on to the VCR control circuits for validation and action. Unlike other manufacturers, an identical baseband signal can also be applied directly (through a wire) into the VCR. Sony call this their Control-S (Ctrl-S for short) port. What this modification does is to intercept the baseband signal within the SmartCable module, invert it, and then translate it into a TTL compatible data stream to send to the Ctrl-S port. The circuit opposite shows how simple this modification is, requiring only 5 extra components. Also shown is part of the original SmartCable circuit, illustrating how the IR transmitter is driven by the carrier, and modulated by the baseband signal (some components have been omitted for clarity).
|
Modification to SmartCable - using LANC connection to supply power. |
|
The circuit above is powered from the
camcorder via the LANC cable. This prevents current drain from the limited
power available in the module.
If you need to use this modified cable with camcorders other than Sony, or with IR camcorders, then you will need the circuit shown on the right. This uses the internal 12v power rail, with a zener diode to maintain TTL voltage compliance at the Ctrl-S output. The pull-up resistor has been increased to 4.7k to minimise current drain, so short Ctrl-S cables (less than 12") are recommended to prevent cable capacitance giving rise-time problems. Note that if this power configuration is chosen, it will of course still operate with LANC-connected camcorders. The reason why I did not choose this configuration for my own cable is because I only ever use LANC, and fitting this circuit inside the module is less convenient from the point of component layout.
|
Modification to SmartCable - using internal +12v supply rail.
|
SmartCable ConnectionsThe picture on the right shows the board inside the IR module. The SmartCable connector has been removed for clarity. Various points have been highlighted to help identify suitable connecting points for the new circuit which can, with care, be located within the module (see example below). As you can see from the circuits above, only 3 connections are needed : Power (+6v or +12v), Tx (from com port), and 0v. In case it is decided to house the additional circuit outside the module, it may be convenient to pick up connections on the reverse of the SmartCable connector header pins. That is why these pins have been identified separately.
|
|
Example of circuit mounted within the moduleThis picture shows how I modified my own SmartCable, adding the components inside the module. (I used the LANC power connection). This was quite a delicate operation, requiring a very fine soldering iron and a jeweller's magnifying glass, not to mention a steady hand and a little patience. The result was worth it, because it makes for a neat solution, with about two feet of Ctrl-S cable emerging from the rear of the module, through a circular slot filed into one of the covers. (When filing the slot, I positioned it so that the cable does not obscure the IR trimmer). The other end of the cable (not shown) is fitted with a standard 3.5mm mono jack.
|
|
Component SelectionAll components are standard items, obtainable from normal retail stores. In the UK, they will be found in the Maplin Catalogue, and on their website.. The transistor was chosen for its voltage rating, current gain, and convenient pin-out to suit the above layout inside the module. This component is not critical - any NPN device of the audio/switching type, with a current gain of at least 100, and a voltage rating greater than 30v will be suitable. If the circuit is to be mounted inside the module, then miniature resistors such as 1/8 watt carbon-film, or Phillips MRS16T metal-film types will need to be used. (Both of these are in the Maplin catalogue, but only the carbon-film variety is listed on the website). The diodes are standard miniature glass types. The screened cable I used was RG174 (2.8mm dia.). The Ctrl-S jack is a 3.5mm mono type.
|
|
How to Use The New Cable.Despite this modification operating like a 004 cable, you MUST make sure that type 006 is selected in SmartCable set-up. If you have used the power connection from the LANC cable, connect the LANC connector to your camcorder and turn it on. If the Ctrl-S VCR that you intend to use has already been successfully used with IR, then you will not need to do anything else. Just plug the new Ctrl-S cable into your VCR and check that it is operating correctly by selecting the Make Movie mode, and pressing a selection of function keys on Studio400's virtual VCR. If this is a new VCR to your set-up, then you will need to train the cable with the VCRs remote. Use the normal Studio400 procedure to do this. Then test the cable as mentioned above. When using the Ctrl-S connection, there is no need to point the IR module at the VCR. If you are using an IR camcorder, then you can dedicate the IR module to this. Adding this Ctrl-S facility to your 006 cable will have no effect on the cable's normal IR capability.
Coming Shortly ......If you do not have a Ctrl-S VCR profile in your Studio400 set-up, and you are having difficulty in training the system from your remote, then I shall shortly be offering a download from this website. In the meantime, if you are desperate, contact me and I will send you a profile by email, with instructions on how to install it.
|
|
