Re: DZ11 EIA dist panel on eBait
> On Jun 30, 2020, at 12:19 PM, Tony Duell via cctalk > wrote: > > On Tue, Jun 30, 2020 at 5:15 PM ed--- via cctalk > wrote: > Connecting a DZ11 directly to the pcb with the connectors won't work directly as expected. >>> >>> Why not? I've linked up DZ11s to the distribution panel PCB with a >>> straight ribbon cable and had no problems. >>> >>> The RFI filters effectively swap odd and even pins in the cable (the >>> pins are straight through the filter but of course you look at them >>> from opposite sides). That's why the short ribbon cables between the >>> filters and the distribution panel are not straight through but have >>> crossover connections.. But if you remove both the filter and the >>> crossover cable it will work as you expect. >>> >>> -tony >> >> Ah, I did not know that, interesting to know. > > I suspect the filters were a later addition. The original idea was to > just connect the DZ11 PCB to the distribution PCB with a > straight-through cable. But the filters had to be added to meet some > interference regulations (is that fcc part 15??), the filters swapped > the pins over, hence the special crossover cables between the filters > and the distribution PCB. That sounds right. Yes, FCC part 15. That arrived somewhere in the middle of the PDP-11 era, so old PDP-11 peripherals and systems don't comply while later ones do. paul
Re: DZ11 EIA dist panel on eBait
On Tue, Jun 30, 2020 at 5:15 PM ed--- via cctalk wrote: > >> Connecting a DZ11 directly to the pcb with the connectors won't work > >> directly as expected. > > > > Why not? I've linked up DZ11s to the distribution panel PCB with a > > straight ribbon cable and had no problems. > > > > The RFI filters effectively swap odd and even pins in the cable (the > > pins are straight through the filter but of course you look at them > > from opposite sides). That's why the short ribbon cables between the > > filters and the distribution panel are not straight through but have > > crossover connections.. But if you remove both the filter and the > > crossover cable it will work as you expect. > > > > -tony > > Ah, I did not know that, interesting to know. I suspect the filters were a later addition. The original idea was to just connect the DZ11 PCB to the distribution PCB with a straight-through cable. But the filters had to be added to meet some interference regulations (is that fcc part 15??), the filters swapped the pins over, hence the special crossover cables between the filters and the distribution PCB. Had the filters been part of the original design then either they would have been on the distribution PCB or the PCBs would have been designed so that all cables were straight (in which case it would not have worked without the filters. -tony
Re: DZ11 EIA dist panel on eBait
June 30, 2020 4:58 PM, "Tony Duell" wrote: > On Tue, Jun 30, 2020 at 3:17 PM ed--- via cctalk > wrote: > >> June 27, 2020 8:05 PM, "Noel Chiappa via cctalk" >> wrote: >> >> https://www.ebay.com/itm/224058116598 >> >> Noel >> >> Looks nice, but the cover, the static filter and the 2 small flatcables with >> twisted wires are >> missing. >> Connecting a DZ11 directly to the pcb with the connectors won't work >> directly as expected. > > Why not? I've linked up DZ11s to the distribution panel PCB with a > straight ribbon cable and had no problems. > > The RFI filters effectively swap odd and even pins in the cable (the > pins are straight through the filter but of course you look at them > from opposite sides). That's why the short ribbon cables between the > filters and the distribution panel are not straight through but have > crossover connections.. But if you remove both the filter and the > crossover cable it will work as you expect. > > -tony Ah, I did not know that, interesting to know. Ed
Re: DZ11 EIA dist panel on eBait
On Tue, Jun 30, 2020 at 3:17 PM ed--- via cctalk wrote: > > June 27, 2020 8:05 PM, "Noel Chiappa via cctalk" > wrote: > > > https://www.ebay.com/itm/224058116598 > > > > Noel > > Looks nice, but the cover, the static filter and the 2 small flatcables with > twisted wires are missing. > Connecting a DZ11 directly to the pcb with the connectors won't work directly > as expected. Why not? I've linked up DZ11s to the distribution panel PCB with a straight ribbon cable and had no problems. The RFI filters effectively swap odd and even pins in the cable (the pins are straight through the filter but of course you look at them from opposite sides). That's why the short ribbon cables between the filters and the distribution panel are not straight through but have crossover connections.. But if you remove both the filter and the crossover cable it will work as you expect. -tony
Re: DZ11 EIA dist panel on eBait
June 27, 2020 8:05 PM, "Noel Chiappa via cctalk" wrote: > https://www.ebay.com/itm/224058116598 > > Noel Looks nice, but the cover, the static filter and the 2 small flatcables with twisted wires are missing. Connecting a DZ11 directly to the pcb with the connectors won't work directly as expected.
DZ11 EIA dist panel on eBait
https://www.ebay.com/itm/224058116598 Noel
