| Are the drivers for the 9-pin serials compliant to DEC423?
We need a 30m serial line between the terminal and the system. I found
the following:
Table of Distances Between Devices
Device Type Speed 4.8 Kbaud 9.6 Kbaud 19.2 Kbaud 38.4 Kbaud
DEC423 device to
DEC423 device 3000 ft 3000 ft 1000 ft 280ft
DEC423 to EIA-232-D 200 ft 200 ft 50 ft 50 ft
DEC422 to DEC422 4000 ft 4000 ft 4000 ft 4000 ft
DEC423 uses the RJ45 Modular Jack, or the Modified Modular Jack (MMJ)
connector instead of the much larger D-type connector defined in RS-449.
DEC423 is signal compatible with the EIA-232-D standard when used for
data-leads-only interconnection, ie, interconnection between devices using
the different standards is possible but the speed and distance restrictions of
EIA-232-D will still apply. DEC423 should always be used be used in
preference to EIA-232-D for direct terminal connection over extended
distances.
EIA-232-D terminals can be connected to DEC423 devices using either an
H8571-x passive adapter, or a H3105-B active adapter. The H3105-B active
terminal adapter is necessary when using an EIA-232-D terminal with a
DEC423 interface if the longer cable lengths obtainable with DEC423 are
required.
|
|
I've been using an H8571-J passive, but I don't presently have a cable
run that long. Can you try the run and see if it works -- depending on
the UARTs (line drivers) and the cabling on the port, I've been able to
wire up runs significantly longer than specified.
Be aware that there are *two* 9-pin serial (DB9) connector pinouts around.
There is the older MicroVAX DB9 pinout (EIA-???), and the newer PC EIA-574
DB9.
I'll send you some relevent (prototype) documentation that's expected to
be included into the manual set for the OpenVMS `Raven' release.
|