This is topic How exact does the SR-D cable need to be? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=001415
Posted by John Walsh (Member # 168) on 09-13-2000, 10:55 AM:
You know that multiple-shielded cable that goes from the Dolby digital soundhead to the SR-D box in the rack... How exact does the length have to be? Could I get away with increasing it by about 1.5 inches?I want to cut it, and splice in a DB25 connector. The crimp terminals will add about 1.5 inches to the overall length.
Posted by Aaron Sisemore (Member # 145) on 09-13-2000, 12:47 PM:
It should work fine, provided that no wires get crossed. I have cut the SRD cables shorter for some installations with no problems, and I know that custom (usually longer than the stock cable) lengths are available from Dolby, so you should be fine... Just make sure that the DB25 connectors lock in in some way so that they can't accidentally disconnect while in operation, as I don't believe its good to run the reader or DA20 with the cable disconnected...Aaron
Posted by Scott Norwood (Member # 30) on 09-13-2000, 01:32 PM:
Wouldn't it be easier just to buy or make a straight-through cable with a DB-25 mail end on one end and a female end on the other?
Posted by Steve Guttag (Member # 268) on 09-13-2000, 03:02 PM:
I have run the SR*D cable as long as 100' (some electrician that I'm sure is real proud of himself ran the conduit by way of China!). No problems and low error rates. There is a physical limit though when the signal will drop of too much but you are talking about inches. I would prefer to keep the cable as splice free as possible though.Steve
------------------
"Old projectionists never die, they just changeover!"
Posted by Brad Miller (Member # 2) on 09-13-2000, 03:26 PM:
Don't cut it. Just put an extension on. I've ran them 55 feet with no problems, but as Steve pointed out before me even 100 feet will work fine.
Posted by Scott Norwood (Member # 30) on 09-13-2000, 04:42 PM:
FYI: I have no idea how closely Dolby follows the standards for serial communications in computer equipment, but the RS-232 spec defines a length limit of 75 feet at 9600 bps.
That's probably a pretty conservative estimate...I've run many serial lines (mostly console cables for Sun servers) for well over 100 feet with no problems...
Posted by Gordon McLeod (Member # 33) on 09-13-2000, 06:51 PM:
It isnot serrial but is video data
If you splice it with a extension I would recomend a shielded connector
Posted by John Walsh (Member # 168) on 09-13-2000, 09:02 PM:
Yeah, I just want to cut the existing cable, and splice in a DB25 male/female. I have a nice shielded AMP connector picked out, and hand-operated spring-loaded clips to hold it in.It's for a "roll-around" DD rack idea we're playing with.
You know where the cable comes out of a CAT. 700? Well, we are also thinking of making a replacement panel that has the same mounting screws holes, but has a DB25 connector (instead of the KO hole.)