Remote Gear Support ..

Tom Easterday tom at
Wed Sep 2 18:11:13 UTC 1992

> I've been poking around (thru the Black Box catalog, for example) for
> equipment to help us support our remote network gear located near the
> NSS to which we attach.  I've had little success at finding the
> right pieces.  I'm wondering if any of you have implemented any of
> these (listed below) solutions, and if so, where you found the 
> equipment to do it; then subsequent sucess/failure information.
> Not in any particular order, here are the functions I'd like to be able
> to perform remotely..  This is a "grandiose wish list", as it were.
> 	* Software switchable dial-up access to serial ports
> 	  on all gear (several ports):
>                                           To Device 1
>                                        +------------->
>                                        |+------------>
>                                        || To Device 2
>    Phone line    +-------+   +---------+++    .
> -----------------| Modem |---| Magic Box |    .
>                  +-------+   +-----------+    .
>                                        || To Device (n-1)
>                                        |+------------>
>                                        +------------->
>                                           To Device (n)
> 	  In this scenario, I dial into the modem to the "magic box",
> 	  and give it some character code or sequence to attach me to
> 	  the specified port.  I can escape back to the magic-box 
> 	  and request subsequent connections without having to 
> 	  redial.  [Black box has one of these for 4 ports, but I hear
> 	  its not too good.  Any experiences?]

CICNet has been using this setup since its inception (1988 or so).  We
use the Black Box 4 and 8 port Code Operated Switches.  Up until recently
we have relied on the site at which the equipment sits to supply the
modem.  We only require 1200 bps.  In short: ****DON'T DO IT*****!!!!!

Ok, now that I feel better, in all fairness, I know that part of our 
problems have been the hodge-podge of modems that are out there.  We are
now in the process of installing the same modems everywhere.  Currently
the setup works about 60% of the time.  There are really flaky things that
go on though with the COS's themselves. If a COS is set on an active port
for whatever reason (and it seems to happen occasionally for no reason)
the modem will not answer because it sees activity on its DTE port.  We are
very careful when logging out of the COS to set it to an unused port 
before breaking the connection with the modem.  Otherwise the next time
we try to dial in it may not work.  I cannot guess how much of our problem
is the modem and how much is the COS but I do know that it is a combination
of both.
> 	* Power Cycle any of "n" pieces of remote hardware via RS232
> 	  interface and ASCII selection.   Ideally, this box attaches
> 	  to one of the ports of the serial switch above, and asks me
> 	  which piece of the "n" attached pieces of hardware should be
> 	  cycled.  [Black box has one of these for a single piece of
> 	  equipment.  It requires a dedicated phone line, and uses
> 	  telco tones to trigger a cycle.]

Yeah, I have wished for that too at times.  We have always relied on
site personnel to power cycle stuff for us.  As we move things into
unmanned sites we will have to consider something like this.

> 	* T1 line switch:
>  Incoming T1     +--------+                 +-----------+
>                  |        |-----------------| CSU/DSU 1 |----> To router 1
> -----------------| Switch |                 +-----------+
>                  |        |-----------------| CSU/DSU 2 |----> To router 2
>                  +--------+                 +-----------+
> 		     ^
> 		     |
> 		     V 
> 		 RS232 Input
> 	  Ideally, this box also attaches to one of the ports on the 
> 	  n-by serial switch above, and has some sort of menu or 
> 	  ASCII code line selection mechanism.  Being a software guy,
> 	  I thought about wiring this up using a switch for RS232 from
> 	  Black Box..  Hardware people informed me that this wasn't
> 	  a good idea.  
I have heard of patch panels for various interface standards (like v.35,
rs449, etc) that are async controllable (ie, the "Switch" you describe)
that would allow you do to this.  Presumably they would be designed to
handle the nastiness that goes on when you slam a digital signal back
and forth through a switch.  You might check with ADC who make oodles of
patch panels for manageable models.

I used to use other ADC patch panels in a previous life and in general they
were well designed and reliable.

ADC's number is 800-733-5511 (Portland, OR).

> Again, these are the thoughts on my mind... and an "ideal wish list". 
> I'd appreciate hearing about any implementations or similar tools
> that you have experience with.
We are currently evaluating a cheap terminal server to replace the COS for
our out-of-band access.  Lantronix makes a TS for about $1200 (Univ price).
Although a bit more expensive then the COS, it provides much more flexibility
(like begin able to telnet to dumb async devices when the network is up,
and being able to have multiple sessions going which makes realtime debugging
of problems easier).   I would be interested if anyone knows of any cheaper
TS out there.


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