Full disclosure on price: right now if I buy one spool, it'll be $0.60/foot to me, I was thinking I'd charge $1/foot for moderate lengths, of course I'm willing to make a deal on bulk purchases, especially if it ends up being local pick-up (here in VA or VCF East). I haven't dressed out cable this large for N connectors in a long time (last stuff was Times Microwave LMR400 for long-range 802.11b stuff) so I'm not sure what the N connectors cost nowadays or how long it'll take me to crimp them on. Not sure how tightly it can coil, but I bet I can fit a load of it in a 15x15x4 box, of which I have plenty. Shortish sections should be able to ship USPS for decent rates, for larger quantities I can use my UPS shipper's account (I have negotiated rates with them). Here's the datasheet on the stuff: https://catalog.belden.com/techdata/EN/89880_techdata.pdf?ip=false DEC spec, orange jacket, plenum rated. Thanks, Jonathan On Tue, Jan 30, 2018 at 6:54 PM, Grant Taylor via cctalk < cctalk at classiccmp.org> wrote:

I believe my guy referenced that listing as his basis for his price. I'm sure freight would bring it up to about the same per-foot cost, if not higher. I am sometimes out near the seller of that particular eBay listing, so I'll send them an email and see if they're interested in a local pick-up deal. Thanks, Jonathan On Tue, Jan 30, 2018 at 7:48 PM, Glen Slick via cctalk < cctalk at classiccmp.org> wrote:

It's simply a good quality 50 ohm terminator, coax type, with a matching connector. If you use standard 10Base5 conventions, the connectors are Type N male, so you splice pieces together with F-F type N barrel connectors, and you terminate with female type N 50 ohm terminators. If you can't find female terminators, a male terminator plus a barrel will of course serve. paul

On Feb 2, 2018, at 5:08 PM, Bill Gunshannon via cctalk <cctalk at classiccmp.org> wrote: More precisely: ground the cable at exactly one point. Any point will do, but it must be grounded (because none of the taps provide a ground). paul

Yes, exactly. And if the cable crosses between buildings, which at least for 10Base5 is plausible, they might have different ground systems. If so, grounding both ends might produce a LARGE current through the cable, possibly enough to be hazardous. (Somewhat different but similar: there's a story about the DEC building at Marlborough, which apparently had two separate power sources at the two ends, from different external supplies. Each was grounded at the service entry, but the two were not bonded together (a code violation). One of the machine rooms had branch circuits from both. One system had a string of large disk drives, RP04 or the like, some fed from one branch, some from the other. As required by the book, the drives were bonded together by substantial braided wire jumpers. One of those got hot, possibly enough to melt it, because the two grounds were at different voltages and the "sneak current" was many amps. I'm not sure if the story is true, but it sounded somewhat plausible.) Many coax connectors have the shell connected to the chassis. But 10Base2 Ethernet connectors are required to be insulated: if you look closely you will (should) see a plastic sleeve between the jack shell and the mounting flange. I don't remember for sure, but it may be that 10Base2 repeaters ground that end, or have an option to do so. That would make sense because you usually have just one repeater on a 10Base2 segment, so grounding there is a logical thing to do. The requirement for controlling grounding is also why 10Base2 connectors are often made with insulating sleeves. For example, the ones DEC sold had plastic shells as an integral part of the connector assemblies (T connectors too). Similarly, you might find plastic shells covering 10Base5 barrel splices or terminators (those were separate from the connectors themselves). paul

OB_Ignorant_Question: Is that the reason why RS232 DB25 has both pin 1 and pin 7?

Similar to safety ground (green) and neutral (white, in the USA) on power wiring. paul

On Fri, Feb 2, 2018 at 4:35 PM, Tony Aiuto via cctalk <cctalk at classiccmp.org> wrote: Handy! I have several transceivers but only 1-2 taps. It would be nice to get some for less than $32, though... I have a small handful of the right terminators, enough for a couple of segments. I'm definitely willing to look at a swap. -ethan

It looks like there's probably enough interest for me to pick up a spool of the stuff. I haven't heard back from the eBay guy, but if nothing else my local supplier is a known quantity. I'll start looking into costs for N connectors, terminator availability, etc. Thanks, Jonathan On Fri, Feb 2, 2018 at 6:12 PM, Ethan Dicks <ethan.dicks at gmail.com> wrote: