http://blog.studio2bee.org/

Terminal Emulation

LINUX/UNIX Servers

 Terminal Emulation.

Linux & Unix have a base of feature rich granularity that allow you to drill-down
to the most basic level of PC control.

Emulating a terminal is a basic built-in function.

Terminal Emulation can be divided into 3 main areas:
The Physical Console or Screen and Keyboard and the Command Shell

Command Line Interface or Shell
http://en.wikipedia.org/wiki/Command-line_interpreter

VT100 Emulation
http://en.wikipedia.org/wiki/VT100

1st the human interface that you operate is called a Console.
Basically a Screen and a keyboard. The mouse is not active here.

Believe or not, a basic Linux/Unix machine lets you connect more that one Console or Terminal
to a Host Machine, and have a different Session on each one.
You can be connected to the Host machine and have Multiple Sessions running on a single terminal.
This is a characteristic of a Multi-User System, of course you must have the permissions and accounts to do this but you get the idea.

These Virtual Consoles are accessed as follows, before you log in to anything:
At the command line in your Terminal or Console, you issue "Alt-F2, or Alt-F3...or Alt-F4...return to Alt-F1"
These commands switch the operating system terminal interface commonly known as tty0 tty01 tty02 act.

To reset a "screwy terminal" if gibberish or garbage is on the screen issue a series of:
Ctrl-J characters and then type [stty sane] followed by another Ctrl-J character.

If the terminal is still wonky, type [reset] and Enter or Ctrl-J.

Still out to sea?, then power cycle the Terminal, not your computer.

These instructions are reminders of ways to get out of a hole.
Your mileage and experience may vary.
Reference Linux Unleashed Hussain, Parker, et al Sams 1995

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OS/X Server

 Traditionally Macs don't have a DB9 Type serial port, unless you have a Xserve Server.
When I had to interface a Mac to a RS422 port for Machine Control in a facility, I had to employ a USB Type adapter to send Commands to a Device.

This was a tricky situation. Often I had to add a RS232 to RS422 adapter to a Keyspan USA-19HS USB High-Speed Serial Adapter. Keyspan is owned by Tripp-Lite now:
http://www.tripplite.com/en/products/model.cfm?txtSeriesID=849&txtModelID=3914

Because a Mac is essentially a Unix Machine, so you have to take a FreeBSD type approach to access a Cisco Console.

Unless you really need to do this, save yourself some trouble and use a PC Laptop or an Emulated Windows machine that can access the Serial port, using an adapter dingy. Your Mileage may vary.

Xserve Server Using Leopard Version:
Serial port access through Terminal in Leopard Server
http://hints.macworld.com/article.php?story=20080218140558128

The Screen command is deployed here, very useful on Macs:
http://en.wikipedia.org/wiki/GNU_Screen
http://www.oreillynet.com/linux/cmd/cmd.csp?path=s/screen

Here is a gem buried deep inside of YouTube, Thanks to MacBookPirate:
Good wisdom by Joel Rennich:
http://www.afp548.com/users.php?mode=profile&uid=4
http://www.youtube.com/watch?v=upsSygfLgJM

Cisco's guide to console access:
http://www.cisco.com/en/US/docs/routers/access/1900/
hardware/installation/guide/19cable.html

Google this : "cisco serial port mac"

Zterm
http://homepage.mac.com/dalverson/zterm/

Use telnet or ssh if you are accessing the Cisco device over a network connection:
Just launch the Terminal App and issue:
telnet <ip.to.router>

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Windows Server

 WARNING: [Do not use a Wireless Connection or an Internet Cafe and such like an Ipad or Iphone to connect to a Router, or Cisco Device,
unless a Secure Connection is insured. And even then I would be careful.]
This installment is all about a Cable Connection.

Console Settings:
9600 8 1 None

Cabling Guide for Console and AUX Ports
http://www.cisco.com/en/US/products/hw/
routers/ps332/
products_tech_note09186a0080094ce6.shtml

When it comes to Windows, the field is fast and clear.
Even though Cisco devices are rooted in the Linux/Unix world, Cisco has a symbiotic relationship with Windows Applications and Interfaces.

Configuration Utilities and Applications usually run atop of Windows.
So be it.

When it comes to Terminal emulation, my experience with the former HyperTerminal app was sufficient.
Google for it if you don't have a Xp Machine.

Now Putty is the ubiquitous version of getting it done.
Remember to toggle "logging" inside the Putty app for an audit trail of your activity.
Click on Logging on the left hand pane:
http://www.chiark.greenend.org.uk/~sgtatham/putty/

By the way, use PumpKIN for TFTP transfers to the Cisco Device for Config Files.
Forget about the older TFTP Server.
http://kin.klever.net/pumpkin

Windows Power Shell which will be highlighted in another article is overkill here.
Although WPS is an excellent addition to the Microsoft Tool set,
for Console access it is just to much for standard use.
Inside of Windows is another matter.

Windows Command Line Interface has been around for a few years:
issue cmd in the run/ search box and run as administrator by right-clicking before left-clicking.

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600 Ohm Interfaces

 Sometimes it's easy to think that with all of the digital technology around us that Analog Engineering has just gone away.

Think again.

http://en.wikipedia.org/wiki/DB_FS

Whenever you interface Audio equipment to the "real world" you're back into Analog domain.
Most manufacturers still adhere to a time proven standard interface, particularly Telco related equipment and Conferencing systems.

To the point, please review this excellent Tech Note from Rane on Interfacing Audio and POTS.
http://www.rane.com/note150.html
http://www.rane.com/pdf/ranenotes/Interfacing_Audio_&_POTS.pdf

Inside the schematic there is a 600 Ohm Hybrid 1:1 Transformer.
UTC Transformers of NY was once the defacto Standard for Full range Audio interface Transformers.
I'm reminded of the UTC LS-140.
It has a dynamic range of 30 Hz to 20KHz @ Max Level of +18 dBm. Wow.

Links to UTC Datasheets:
http://www.bunkerofdoom.com/xfm/UTCCHART/utc_DATA.pdf
http://leedsradio.com/parts-transformers.html


Do a ebay search for UTC Transformers [United Transformer Corporation] and you will be surprised that various models like the:
UTC LS-68 list for US $683.20 and the UTC LS-61 list for US $295.00.

Look around in the your shop and see if you have some UTC's collecting dust.
Use them or Sell them.

By the way, some one in Bulgaria is selling a SONY SUPER METAL MASTER 60 AUDIO CASSETTE SEALED for US $150.00.

Look at this link for a Vintage RCA BK-11 Ribbon Microphone MINT for C $2,680.00.
http://www.ebay.com/itm/Vintage-RCA-BK-11-Ribbon-Microphone-MINT-100-Original-/250910102624?pt=LH_DefaultDomain_2&hash=item3a6b685460

Here's a rare find: NEW (!) VINTAGE REVOX B77 MKII STUDER REEL TO REEL TAPE MACHINE B 77 MK 2 SEALED
US $3,950.00
http://www.ebay.com/itm/NEW-VINTAGE-REVOX-B77-MKII-STUDER-REEL-REEL-TAPE-MACHINE-B-77-MK-2-SEALED-/190585549969?pt=Vintage_Electronics_R2&hash=item2c5fc8b491

Analog still rules.
http://www.analogrules.com/   More,

Schitzen Giggles

 When you hear the expression, "We don't need no stinkin' engineers" just politely smile and quietly raise your rate.

Some people out there are shamelessly taking advantage of this:

I've often said that if I were smart when I started in this industry that I should take out some stock in Belden and other Cable manufacturers.

When I worked for PBS when we built the Facility at L'Enfant plaza, we must have used "miles" of Coax Cable.
Cut forward to 2011: http://finance.yahoo.com/q?s=BDC

$29 per share shouldn't justify a certain vendor pricing of $10,000 / meter for RCA interconnect cables.
And then again, maybe not.

http://www.analogrules.com/snakeoil.html (Click on Stealth)
http://www.audioholics.com/education/cables/top-ten-signs-an-audio-cable-vendor-is-selling-you-snake-oil

Spaceweather for Geomagnetic Storms and Solar Eruptions
http://spaceweather.com/

Spectrum mapping of TV Channels:
http://www.tvfool.com/
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