• Please review our updated Terms and Rules here
  • From now on we will require that a prefix is set for any items in the sales area. We have created regions and locations for this. We also require that you select a delivery option before posting your listing. This will hopefully help us streamline the things that get listed for sales here and help local people better advertise their items, especially for local only sales. New sales rules are also coming, so stay tuned.

10BASE5 Transceivers

NeXT

NeXT

Veteran Member
Joined
Oct 22, 2008
Messages
8,149
Location
Kamloops, BC, Canada
Yes, the stuff with the vampire taps.

10BASE5Node.jpg


My new workplace has a maintenance yard for the regional cable company behind it and several times now I've seen a few meters of appropriately sized coax go to the dumpster in the alley. I don't think they'll mind me dumpster diving for network cable. ;) If I can get two taps I wanna see if I can get creative.
 
Oh yuck, that brings back some really bad memories. RG8/U garden hose cable with those tricky taps. 10Base2 was actually a big improvement...
 
Ughh!

A bad tap installation was impossible to troubleshoot. Even worse than a bad cable in a 10base2 network (at least you could unplug and swap cables/parts on those). I can understand wanting 10base5 for a museum exhibit but to actually run it :crazy:
 
Yup--all you needed to make your life miserable was a munged-up vampire tap that resulted in a short. Everything goes down and you don't know who's causing the problem. An issue on a long run could drive one to drink.
 
Chuck(G) said:
Yup--all you needed to make your life miserable was a munged-up vampire tap that resulted in a short. Everything goes down and you don't know who's causing the problem. An issue on a long run could drive one to drink.
Click to expand...

I have a Tektronix Cable Scout. This beauty of a device lets me hang it off one end of a line of coax and it will tell me where any anomalies are along the entire length of the cable. I've found it very handy when cables in the floor or walls is rodent damaged.
 
Yes, but for those of us that cut our teeth in this stuff, those TDM testers where great and it was standard equipment for installers.
 
I remember sending packets over thick ethernet, and seeing it routed in steam tunnels at $undisclosed_location. But I have not experienced the dubious pleasure of installing a vampire tap or hunting down a bad tap. I wouldn't mind having a short run of the yellow data hose taking a lap around my machine room.
 
In a previous century, I preferred RG-58/U over that silly newfangled 10BaseT stuff with all of its superfluous hubs and whatnot. Star topology seemed wasteful and overly complicated to an EE student who's comfortable with properly terminating a coax cable at both ends. As it turned out, thin net was too complicated for even an EE professor to understand, as demonstrated by finding a T adapter on an uplink jack wall plate with coax wandering off in both directions to workstations which oddly had trouble talking to the rest of the campus.
 
NF6X said:
In a previous century, I preferred RG-58/U over that silly newfangled 10BaseT stuff with all of its superfluous hubs and whatnot.
Click to expand...

My first 10baseT network (early 1991, pre-EIA/TIA-568 ) still used 10base2 as a backbone between the hubs, and for a few systems that didn't want to connect to anything else (e.g. DEChub 90 ethernet backplanes for customer systems). It was neat being able to connect individual ethernet nodes over twisted pair in the building's phone wire (6 pair plenum category 4). Still not much fun to troubleshoot when there were problems, though (I remember rescheduling a Friday afternoon flight because the ethernet melted down and I was busy partitioning the network looking for the problem). When 10/100 Mb/s switches became available that made things much easier because the collision domains were all isolated. To this day I use managed switches whenever the budget will allow because of the ease in troubleshooting, but in fact there are many fewer problems than in the early days, and most problems are isolated to an individual cable run.
 
Last edited:
NeXT said:
...
My new workplace has a maintenance yard for the regional cable company behind it and several times now I've seen a few meters of appropriately sized coax go to the dumpster in the alley. I don't think they'll mind me dumpster diving for network cable. ;) If I can get two taps I wanna see if I can get creative.
Click to expand...

Heh, that can probably be arranged. While RG-214 or RG-8 can be used in a pinch for thicknet backbone cable, true ethernet cable has the allowable tap points clearly marked on the orange jacket. I can get pics; we have at least a quarter-mile of the stuff here with taps and AUI drops intact. Make sure you have the proper terminators, and that one end is properly grounded. I might have a tap kit here somewhere.....

I cut my networking teeth on installing the NIC and drivers on DOS machines, using 3Com 3C501, 3C503, 3C505, 3C507, and 3C509 cards back in the early 90's. The factory for which I worked quickly ran out of legal tap points and started using Cabletron's MT-800 Multiport Transcievers (see: http://www.dilette.com/main/dilettesales/Cabletron_MT-800.html ) to get eight workstations on each tap (the MT-800 has eight workstation-facing AUI ports and one backbone-facing AUI port).

Troubleshooting jabbering hosts was a pain, even with the multi-segment design they had.

Up until about two years ago we had one operating thicknet segment with an FOIRL transceiver pair for one particular remote location that we actually wanted to throttle to 10Mb/s. The client using that location finally ponied up the cash to get a 1000Base-SX uplink installed.... Those old FOIRL transceivers were so old that they were using SMA-type fiber connectors.

This site was an early adopter of routing technology in its earlier days, using Proteon 68020-based routers with four AUI ports and an 80Mb/s fiber Pro/NET token-ring backbone. Still have three of the Proteon routers, all the manuals, and three of the Pro/NET-80 modems with their weird non-ST bayonet fiber connectors.....
 
So here's a somewhat-related question: Why are 10base5 nodes spaced at 2.5 meter intervals, but the minimum cable between tees on a 10base2 network is .5 meter? I mean, the frequency and timing is the same, so shouldn't the standing wave problem you're avoiding with node spacing also be the same?
 
Uniballer said:
So here's a somewhat-related question: Why are 10base5 nodes spaced at 2.5 meter intervals, but the minimum cable between tees on a 10base2 network is .5 meter? I mean, the frequency and timing is the same, so shouldn't the standing wave problem you're avoiding with node spacing also be the same?
Click to expand...

The distance was chosen very specifically to avoid reflections (2.5 meters is not a resonant length at any of the frequencies involved (taking into account the velocity of propagation in the dielectric); every impedance 'bump' along the cable represents a reflection point, even with the vampire tap system the impedance match of the transceiver is not perfect and it is less perfect with N-connected transceivers). With the longer 500-meter length of the 10Base5 maximum segment, reflections are much more critical. 10Base2's 200 meter length makes the reflection problem less critical, and so the tight 'exactly spaced at multiples of 2.5 meters' rule didn't apply.
 
Someone here wanted proof I had found cable.

IMG_5619.jpg


It's not your classic "frozen yellow garden hose" and it's not entirely to the spec but with the longest piece being only 30' long I doubt I'll be running into signal loss issues due to the length.
 
You must log in or register to reply here.
Back
Top