|WikiProject Computing / Networking||(Rated C-class, Low-importance)|
debugging 10base2 networks
The "expensive" equipment mentioned is probably a fluke network analyzer or similar. This device can give you the distance to a fault in the wire, which can greatly help. However, you don't need that, and shorts are not difficult to find really. There are two easy methods:
- play Pass the Terminator: Grab a terminator, and replace one end of the cable at the T with the terminator, and see if that half of the network now works. Do this until you find the fault.
- Multimeter test At the located fault: Set your multimeter to volts and check the voltage at the open end of the cable. If it is zero, there are no live computers on that wire, or you have a short or open. (If there is voltage, STOP!) Then switch to ohms and test the cable end again. It should show about 50 ohms. If it reads much higher, you have an unterminated line (open). If it reads zero ohms, you have a short. Note that if you measure at the T where the computer connects rather than where a cable connects, it should read near 25 ohms (two terminators in parallel, 1/(1/50+1/50) = 25) NOTE!! This method is a bit DANGEROUS -- if you have voltage on the wire and use your multimeter in ohm mode, you could damage the meter (or more likely, blow its fuse). This is why you MAKE SURE the line is 0 volts before measuring ohms.
Despite the ease of this, I'm glad my 10base2 days are long over. It's so much easier to plug in the CAT5 cable and look for the blinky lights. The biggest problem with 10base2 cables is that computers are in a chain, and one kicked out cable takes out your whole network. --ssd 05:04, 30 Jul 2004 (UTC)
- Another thing i heared from a collage lecturer was that students would half-unplug thinnet cables so they looked connected from a distance but didn't actaully make a connection. Plugwash 16:50, 30 September 2005 (UTC)
Anyone who ever maintained such a network for years will probably loathe them as much as I do. Our home (and company!) network (at it's 10base2 peak in late 2003) consisted of 2 iMacs via switches, one Router, one Notebook and 5 PCs all on one chain of BNC cables. Though the cables were *mostly* shielded from direct harm (cats chewing through network cables isn't a problem you usually consider when putting up a network) eventually (after about 5 years) they started to act quirky. Interestingly, the problems never occured in the patched up bits cats had gnawed on, but always at apparently random spots all over the network. The "pass the terminator" game had a tendency to be completely unreliable and the network would phase in and out with no interaction whatsoever, sometimes curiously spliting the network in half (which was technically impossible except for the PCs sharing the same switch.
As some PCs were already connected to the same switch via Cat5 (which was then connected to the rest of the network as part of the 10base2 chain), we eventually decided to get rid of the whole mess and replaced it with what must have been more than 100m of Cat5 cables. We also waved the company which set our network up good bye for good. It hasn't been down once ever since and if any cable would fail now, it would be both easy to replace (the BNC cables were sunk into the walls (some places apparently even OUTSIDE the house) and all but easy to replace -- we had to leave some good length of cable in place, just cutting off the ends because we couldn't just tear down the entire wall to get rid of the cables) AND easy to track down. Also, impact would be minimal, as the switches effectively create sub-networks.
10base2 and 10base5 compatibility
Were 10base2 and 10base5 compatibile with each other? I've taken a quick look at 802.3 and other than some specs being tighter for 10base5 and the use of better quality coax (which between them allow bigger networks) I can't see any real difference. Plugwash (talk) 02:24, 8 March 2009 (UTC)
- You are correct, they use the same electrical signaling (or if not the same, close enough as not to matter). Although the specs didn't suggest it, I did hear of cases where people took the terminator off of the end of a 10base5 run, replaced it with an N-to-BNC adapter, and just continued the run with RG58... eventually ending in a terminator, of course. And they worked fine. Jeh (talk) 23:59, 15 April 2009 (UTC)