Addendum to my previous message.
I think you would be best off with several compact 8 to 16 port terminal
servers, placed near the devices they service; that way, you just have
a few long Ethernet cables and a bunch of short serial cables, rather
than a bunch of long serial cables. Uhh, unless of course you want to
take a big, heavy Xyplex Network 9000 off my hands (40 serial ports and
40 Ethernet ports, with room to expand), in which case a big centralized
terminal server is just what you need! ;-)
On the DECserver and similar machines, with a terminal plugged in, you
get a prompt you can "connect foo" to connect to a LAT service, or
"telnet foo" on TCP equipped machines. Some also allow
"connect local port_1" to connect to a local serial port without going
through a LAT service. On machines that support reverse LAT, you can
associate port(s) with a service, and connect to those ports remotely.
You could also connect to the command prompt with MOP and on some
models with LAT, IIRC. On TCP equipped models, you could telnet in
(sometimes to 23 and sometimes to a high port) and get to the command
prompt (sometimes after authenticating). Also, each serial port could
have a high TCP port associated with it for inbound connections. Some
machines could associate an inbound TCP port with a service, for port
rotaries, IIRC. Note that I am painting DECservers, ETS, MAXservers
with a broad brush here; some brands may not support all features.
Oh, and you could also set ports to have a dedicated service, so they
don't get the CLI. And you could set up menus, too.
On the Annex you get a non-DECserver-like CLI from a terminal or
modem dialin, and you can telnet out from there -- or, IIRC, it can be
set to automatically telnet to a given host, or set up with menus.
Coming from the network, you could telnet to port 23 and get a prompt
for which serial port you wanted to connect to. The ports could be
arranged in rotaries and if all ports were busy you could wait for one
to become available. At the prompt for the rotary name you could also
ask for the CLI. Like the DECservers, you can connect directly to ports
by using high TCP ports. (Some models of?) the Annex could also have
multiple IP addresses, if I'm not mistaken, and could be set up so that
a telnet to each address would end up at a different serial port. I
believe Annexes were popular with universities, but some corporations
and ISPs used them too. They later had a "Remote Annex" RAS product
with built-in modems, similar to the Ascend MAX and Livingston PM3.
On the LANrover, if you dial in on a modem, or if you telnet in, you
get a login prompt, and once you authenticate you go to the CLI -- or
a given account could be set in the account database to go straight
to a specific destination. From the CLI you can telnet out, or you can
connect to ports by name. There is no provision for direct telnet to
a serial port by a high TCP port.
-- Adam
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