How long is the cable for the DigiSnap? Is it extendable?
The DigiSnap is connected to the camera via the serial cable offered by the camera manufacturer. The DigiSnap does not come with a cable to connect to your camera. Most other compatible cameras are sold with with PC type serial cables included.
If your camera came with this cable then you are set to go! If not, you will have to purchase one from a camera retailer. When we have them in stock, we are happy to re-sell the Nikon SC-EW3 as a service for those people buying DigiSnaps for use with Coolpix 990's and 880's.
If you'd like to operate remotely (i.e. more than a few feet from the camera), then you may need a longer cable. As the DigiSnap uses the industry standard DB-9 serial port interface, you may buy additional serial cables from any computer / office retailer, and daisy-chain them together to reach the distance you want. Serial cables are commonly available to 25 ft lengths. If you want to get really remote, then you may need a custom cable made.
If you are technically inclined, then it's a very easy project to do-it-yourself. This serial port only needs pins 2, 3, and 5 connected, so you could get by nicely with a 3 wire cable, or even a 2 wire with a shield (connected pin 5). For those not so technically inclined, there are any number of small computer stores that could fabricate the cable for you. If all else fails, Harbortronics can also fabricate a very nice custom cable for you, but as this is not our primary business, we would likely charge more than other places.
We have an old spool of network cable in the lab (about 700 ft of cable left on it), which we have used for testing, and found that there was not problem operating to that distance. There is a big caveat here though... the RS232 specification is rated to only 50 ft at the maximum data rate (230 KBaud), although everyone knows it it'll run farther than than, particularly at low data rates. To get it to run at really long distances you might be careful with cable selection, and try to isolate the signals by using twisted pairs... Cat 5 network cable is cheap and excellent for really long runs.