Getting a Sun Ultra 5 To Work

On 8/22/2011 1:13 PM, Chuck Guzis wrote: Exactly. A lot (all?) of my RS-422 applications were point to point, I think. RS-449 on the DB37, and RS-530 on the DB25. With the addressable nature of RS-485, they had the tendency to be multidrop more often. There were some Allen Bradley PLCs, Scada systems, and the like to which we were interfaced. I dealt with both async applications, and sync applications between routers and CSU/DSUs when leased lines were much more popular. Cisco had(has) what they called a 5-in-1 interface(later more, maybe 8-in-1) with matching cables that had a high-density 60-pin connector on the router side, and then the appropriate connector on the other side. With shorting groups within the HD60, it told the cisco hardware which electrical standard to pick and use. The cable would also tell the router if it was appearing as a DTE or a DCE, and this would control directions of signals -- but also whether clock generation was allowed on the interface. DCE's could provide/source the clock, but DTE's could receive only. The router was typically the DTE, with the CSU/DSUs, multiplexors, etc being the DCE's. Normally the clock would be generated on the leased circuit, and then the CSU/DSU's on both ends of the link would recover the clock, and then sync the transmissions of the routers to it. We had one router that had in essence a frequency counter, and it could actually display in real-time(more or less) the current rate present on the clock interface. Cisco also had a DTE/DCE crossover cable with HD60's on both sides. One side was shorted to be a DTE and the other a DCE. You would enable clocking on the DCE side, and it would allow two routers to communicate back-to-back without the need for any intermediate equipment. I would also be remiss if I didn't mention V.35, probably the most popular serial sync interface on routers. Keith