Here is a pic
Here is a interface that I made long time I made Schematic of to post easy one to make.
Last edited by badass; 27-07-09 at 05:20 PM.
Look Here -> |
Here is a pic
best4less (27-07-09)
Homebrew construction is fun!
The above circuit design is very similar (if not identical, I can't remember) to Jomac's season interface that was popular a few years ago. It's relatively simple and cheap to build because, unlike most seasons that use a MAX232 for the RS232 interface, it just uses transistors to perform the necessary logic inversion. Although that's a dirty trick it works fine with most PCs and receivers provided the cables aren't too long (because the RS232 side is higher impedance than RS232 standard, and the logic side exposes the receiver's CAM to noise and ESD).
There's an error on the above schematic though. On the PCB connector where the pins are numbered "3 1 4 2" it should read "1 4 3 2".
So from top to bottom the functions of the PCB pins are:
GND
no connection
I/O
CLK (not used by season interface)
/RST
VCC
The leads going to the transistors are:
4. I/O
3. /RST
2. VCC
1. GND
The top BC548 transistor inverts the CAM's I/O signal to drive RS232 RXD (pin 2 of DB9 Female connector).
The middle transistor inverts TXD (from pin 3 of DB9) and pulls I/O to ground when the PC sends ATR or replies to commands.
The bottom transistor inverts /RST (the CAM's active low reset output signal) to drive RS232 carrier detect CD (pin 1 of DB9).
Any NPN bipolar transistor can be used, eg BC547/BC548/BC549/BC337/BC108/2N2222. They're all in common emitter configuration with ground provided by DB9 pin 5 on the PC, corresponding to ISO7816 pin C5.
The three pullup resistors shown as 4.7 on the schematic should of course be 4.7K They draw on VCC output from the CAM, ISO7816 pin C1, which for most receivers is +5V.
Be aware that at times there may not be +5V at the interface. That's normal: if the PC software isn't ready and fails to send ATR after the /RST (CD) pulse then the CAM will probably switch off the power after a short time and give "invalid card" message.
Those interested in building themselves a season can find more .
Thanks for sharing badass, it's always interesting to see others' work.
Last edited by gw1; 27-07-09 at 06:00 PM. Reason: corrected C1 -> C5 typo
best4less (04-12-11)
GW1 you are incorrect the pin outs that I posted are 100% correct. It's one I have been using for about 10 years for programming radios. I just added the PCB there are other parts on other side for programming card while in box via a switch but didn't post them not to confuse people but obviously I did anyway.
PS I use a 2.5 M cable from computer to it.
Last edited by badass; 27-07-09 at 06:26 PM.
Badass, I don't doubt that what you built is correct
I'm just pointing out that your hand-drawn numbers don't make sense, IMO.
That's not meant as a criticism, god knows I make mistakes all the time!
Anyway if people building your circuit have problems they can try my suggestion:
best4less (04-12-11)
For comparison here's the schematic for Jomac's season interface, from 2003.
Last edited by gw1; 27-07-09 at 05:08 PM. Reason: resized image
best4less (04-12-11)
I will apologize I had a lot of problems last night with Imageshack and didn’t not notice that the wrong URL for pic was there but I had fixed the problem and I thought it saved when I edit post but obviously it didn’t go through. Best4less was in thread when I notice the fault as I told him it was wrong pic but it must not have save after edit not sure why.
But as I said I apologise.
best4less (04-12-11)
Thanks guys. I actually wondered what was special about a jomac interface but was always too scared to ask :0
Leroy
XCRUISER HDSR600HD twin sat and terrestrial receiver $OOS *
XCRUISER HDSR385 Avant - sold out$OOS UltraPlus DVB-T and DVB-S2 tuners $49 Remotes $OOS
Ignore last post. sorry posted wrong thread
Last edited by Danny; 27-07-09 at 09:49 PM. Reason: Wrong thread
couldnt see why not
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