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DECbrouter questions

hush

Experienced Member
Joined
Feb 7, 2022
Messages
316
Location
MD, USA
hey all! i'm working on building a retro lab/DMZ with DEC networking gear, and i'm a little confused trying to figure out how my DECbrouter 90T2 will connect to my existing LAN. according to the documentation i can use the BNC port on the top of the unit as well as the RJ45 port at port 0, but it looks like both of these are disabled when the unit is installed in a backplane, which is my intended configuration (a 900 backplane specifically):

Code:
Twisted Pair (10BASET) connector–Connects the
DECbrouter 90 to a 10BASET twisted pair. Not used
when the DECbrouter 90 is installed in the DEChub 90
backplane.

[...]

Port 0 network connector (BNC)–Connects the
DECbrouter 90 to the work group ThinWire segment.
Not used when the DECbrouter 90 is either installed
in the DEChub 90 backplane or connected through the
twisted pair (10BASET) connector.

the documentation doesn't mention the 900 backplane, but i can't seem to find documentation for this model that does. i would assume the behavior is the same. that leaves me with ports 1 and 2, which have an odd configuration. the cable used for RS232 ethernet connectivity is DEC P/N BC12L-06, with the following connector configuration:

Code:
Des 50-way, straight, micro-champ (DECbrouter end),
             Connector 2  25-way, straight, male, D-type (RS232 end).

i haven't been able to locate this cable, so i may need to make my own. thankfully a pinout exists here in case anyone else stumbles on this. does anyone know if i'm misunderstanding the documentation or my configuration, or, if needed, where i could find one of these cables?

thank you!
 
Last edited:
I have some of the BC12G V.35 versions of the cable. I bought them as new from Vnetek Communications a few years ago, along with a couple hundred MMJ plugs for making my own MMJ cables. As far as I know at some point they had acquired what was left of Digital Networks some time ago. Unfortunately they seem to have gone out of business a couple of years ago. I wonder what happened to anything they had left of any Digital Networks hardware.

Maybe I should have also bought a final release copy of DNAS software from them when it was still available. There is a CD image of DNAS 2.4 on archive.org, the final version might have been DNAS 3.6. Haven't found a copy of that anywhere.

https://archive.org/details/digitalnetworksnetworkaccesssoftware24
 
To shed some light:

Most if not all DECxxx-90 modules have the BNC connector at the side. As mentioned before, these are disabled when you use the DECxxx-90 module in a DEChub-90 or -900. When used in DEChub-90 or -900 the internal 10Mbps network (inside the DEChuib90/900) is used in stead.
The DECbrouter 90 T2 when used in the Hub should have one network port on the front and one network port on the HUB internally. The internal HUB network on the DEChub-90 has a BNC at the righthand side of the HUB... or you can use DECrepeater in a variaty of flavours: even 10baseFL (slow ethernet over fiber) available. The DEChub-900 needs a 10Mbps ethernet repeater or switch to bring the internal network to the outside.
The DECbrouter 90 T2 has one or two serial ports for external modems and leased lines. The software inside the DECbrouter 90 is Cisco IOS.
 
good info, thank you! i'm reading through the DEChub 900 manual and the only connector i'm able to see is for out-of-band management, 1x RJ45 and 1x DB9. i may be missing it but the manual doesn't seem to mention connecting the hub to an external network, only a management terminal.
 
good info, thank you! i'm reading through the DEChub 900 manual and the only connector i'm able to see is for out-of-band management, 1x RJ45 and 1x DB9. i may be missing it but the manual doesn't seem to mention connecting the hub to an external network, only a management terminal.
Correct: no network plug on the DEChub-900... <quote>The DEChub-900 needs a 10Mbps ethernet repeater or switch to bring the internal network to the outside.</quote> You plug repeaters or switches into the DEChub-900 and that will be your local network. One side of the DECbrouter 90T2 will be in that network too. You do have modules for your DEChub-900...? Such as DECrepeater-90 or -900 etc??
 
It's a long time ago but... you have to configure the DEChub to "connnect" the module to a "lan" in the backplane.
There was a utility program to do that. Maybe HUBwatch?
it's been too long

joe
 
Correct: no network plug on the DEChub-900... <quote>The DEChub-900 needs a 10Mbps ethernet repeater or switch to bring the internal network to the outside.</quote> You plug repeaters or switches into the DEChub-900 and that will be your local network. One side of the DECbrouter 90T2 will be in that network too. You do have modules for your DEChub-900...? Such as DECrepeater-90 or -900 etc??
that would explain it! i have a 16 port DECrepeater coming my way, i was just trying to make sure i had all my ducks in a row before everything arrives and i start poking at it.
 
I tried my DECbrouter 90T2 in one of my DEChub90s: bummer, it has only one ethernet port (!). Two serial interfaces for datalines. Software is IGS-BFPX version 9.14 copyright 1993 Cisco Systems Inc. Booted from Flash. Device has 1MB, plus 32K non volatile configuration memory and 4096K bytes Flash on CPU board. Btw, processor is 68030.

I was looking for a hidden push button to reset to factory defaults, but did not yet find.

I think Joe is right about the config of DEChub-900: it has multiple backbone networks, VLAN capable and when using the more advanced series of modules it needs configuration. In good DEC tradition that can be done in Whatever-COMMAND_LANGUAGE. (Not denying tools can be handy here).
 
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