

	This file contains information and some answers to questions
	about Xremote. 


Subject: 1: )   Xremote verses SLIP
Subject: 2: )   Xremote tuning for UNIX
Subject: 3: )   FastComm  Modem Register settings
Subject: 4: )   Telebit T-2500 settings
Subject: 5: )   General Terminal Server settings


	------------------------------------------------------------


Subject: 1: )   Xremote verses SLIP


Xremote and SLIP (as far as we know), are ignorant of the speed of
the transmission line, so the more appropriate comparison would be
Xremote vs SLIP as opposed to performance based on line speed.

Our literature states Xremote is about 10 times faster than SLIP,
this is regardless of line speed. Obviously, if your line speed is
9600, your performance will be better than if the line speed is 2400,
this holds true for both Xremote and SLIP. SLIP has an overhead of
roughly 41 bytes per packet, while Xremote has a
builtin overhead of 5 bytes per packet, so when the variable length X
data is encapsulated by these two methods, a SLIP packet will be
larger. Also, X over SLIP has no compression applied to it, while
Xremote is compressed by two methods before the 5 bytes of overhead are added.

So how do we get the 10 times faster for Xremote. Well, if you
measure consecutive X keypress events, which contain 32 bytes of
data, SLIP would require about 32+41=73 bytes per packet, while
Xremote could squeeze the consecutive keypresses down to 3 bytes+5
overhead= 8 bytes, which gives you about 10 times
faster.

Or, you can look at the echoing of keystrokes, (typical in Xterms),
which consists of 3 Xrequests, 1)ImageText to eliminate the 'block
cursor', 2)ImageText to place the character where the cursor was and
3) another ImageText to replace the block cursor. This makes the
total X byte count 3*32=96. If you do this over SLIP, the packet size
is 96+41=137, over Xremote the packet size would be down to about 12 bytes.


Subject: 2: )   Xremote tuning for UNIX

HOW TO SET UP YOUR UNIX ENVIRONMENT FOR FAST XREMOTE 

There are several things you can do to improve your performance 
running XRemote.  As you know, the penalty you pay in terms of 
performance comes during the down-loading of fonts and resources.  
You want, then, to minimize the number of these that you download, 
and minimize the frequency with which you need to download.  

You should not use xrdb to send resources (e.g. xterm*jumpScroll:  
off) to the server, as you probably do when you're directly on the 
network.  These resources will take effect just as well when the 
client starts up if they reside in the file ".Xdefaults" in the 
user's home directory.  By customizing your resources this way in the 
.Xdefaults file, there is no need to download resources to the 
server.  Hence that wait time is eliminated. (Note that these 
resources must be defined in .Xdefaults itself, rather than in files 
that might be #include-ed in .Xdefaults.  It also means that if 
you're starting clients on other machines, you must have a home 
directory on those machines and a matching .Xdefaults file in each.) 

Fonts may also be selectively downloaded.  If you try to keep your font path 
short, no longer than necessary, you will benefit.  On a network, many of us 
exploit the luxury of including every known font in the universe in our font 
paths, just in case we might start a client that might want to use them.  If 
you know what you're going to run at home, then you can include just the set 
of fonts that will be needed, and no more.  And you may add them at 
the time they will be needed, not in advance.  

Furthermore, if you make good use of the built-in fonts (cursor, 6x10, 6x13, 
8x13, 9x15, 9x15bold, 10x20, fg-22, fixed, and vtsingle), you can also 
eliminate download time.  I use xmh and xterm 98% of the time, always with 
built-in fonts.  My session initially takes 10 to 15 seconds to come 
up.  Examine closely the messages in the Diagnostic Session for ideas 
on which fonts are still downloading.  

Another alternative is to set up a special font directory with JUST 
the specific fonts you want.  That is, for applications like xmh, you 
don't need the bold, oblique, or multipoint versions of a font style, 
so don't include those in your lean, special directory.  

Also, if you use a small window manager, such as uwm or twm, that 
will be more suitable than something like mwm or olwm.  In 2.3, the local window
manager further improves the responsiveness of window manipulations.  

So, with a little planning, you can set up XRemote to work much 
faster and more efficiently.  


Subject: 3: )   FastComm  Modem Register settings


command AT#?  output:

        ATE     Terminal Echo              ON
        ATM     Speaker Control            1
        ATP     Terminal Parity            Space
        ATQ     Result Code Quiet          OFF
        ATV     Result Code Verbose        ON
        ATX     Result Code Set            4  Full
                Call Progress                 Full
        ATY     Long Space Disconnect      OFF

        AT&B    Freeze DTE rate            ON
        AT&C    Carrier Detect mode        1
        AT&D    DTR mode                   2
        AT&H    Transmit Flow Control      1 - CTS
        AT&I    Receive Flow Control       0 - None
        AT&J    Phone Jack Select          RJ-11
        AT&M    MNP and Sync mode          0  Async  No MNP
        AT&N    Data rate                  0  Highest Speed
        AT&P    Dial pulse ratio           US
        AT&R    Sync RTS mode              0
        AT&S    DSR mode                   0
        AT&T    Self Test Modes
        AT&Y    Break handling             2
        AT&Z    Stored Number dialing storage


command AT#?S output:

            S REGISTER CONTENTS
     REG   VALUE         DEFINITION
     000    000    Rings before Answer
     002    043    Escape Character Code
     003    013    CR Character
     004    010    LF Character
     005    008    Back Space Character
     006    003    Dial Tone Wait
     007    045    Wait for A/T
     008    002    Pause in Dial String
     009    006    CDET Delay
     010    008    CDET Loss Delay
     011    070    Tone Dial Time
     012    050    Escape Guard Time
     018    000    Self Test Timer
     025    005    Delay to DTR
     026    001    RTS to CTS Delay
     030    017    XON Character
     031    019    XOFF Character
     040    050    Break Time
     043    000    Protocol Select
     055    050    Hang-up Reason
     056    000    Special Modes
     057    000    Data Meter Time
     061    255    Max Redials
     065    000    Special Connect mode
     068    000    MI-MIC mode
     072    000    Inactivity Timer
     073    200    MI-MIC Delay
     076    060    Inactivity Timer Scale

Subject: 4: )   Telebit T-2500 settings

FYI

How to install Xremote and a Telebit T2500 curtesy of Lawrence Livermore Labs.

Here are step by step directions to fire up an NCD
display running Xremote, hooked to a Telebit T2500.
These pendantic directions are possibly more useful
than telling the user to use the "factory settings"
on the display, set the display to boot with the
Serial Session window active and use the string
AT ~ &F S58=0 S50=6 S54=3 S55=3 &W
to configure the modem.

We just took an NCD display, and a Telebit modem,
right out of the boxes from the factory and tried
these directions.  They worketh, and there were no
hidden manipulations.  You will have to excuse us for
going through all the detail with regard to cabling
and power switches, but one is never sure just how
much detail a given user needs.

1) Unpack the modem and X display from their boxes.
2) Assemble the display, you might want to check that
there really is an Xremote PROM set plugged into the
ethernet interface card, these proms should have
"XREMOTE 16", "XREMOTE 19," or "XREMOTE 17" printed on
them, according to the type of the display.

3) Connect the modem to the phone lines, connecting the
wall jack to the "to line" connector on the back of the modem.
Plug the modem into its power supply and the supply into
the wall, with the modem power switch OFF.  Connect the
modem to the X display with a RS232 cable, with all wires
straight through.  DO NOT USE A NULL MODEM!  Connect the
mouse to its jack on the back of the display, the keyboard
to its jack, and the video cable to the base.  Plug the display
in after checking that its power switch is off.

4) Turn the modem power switch on.
5) Turn the display power switch on.

The display will now go through its self test and proceed to
unpack code and data from the Xremote PROM set.

unpacking code...unpacking data...done

will get printed.  X will then come to life after some debugging
messages are printed on the display.  The screen will be stippled
and the "X" cursor will be in the middle.  The mouse should move the
cursor.

6) Hit the setup key once.
You will get the "Main Menu"

7) Use the left mouse button to toggle the "use Led 1 for" to
"Network Activity"

8) Select "Serial Parameters" with the left mouse button
to get the "Serial Port Parameters" menu.

Confirm the factory settings:

	Data Bits: 8
	Stop Bits: 1
	Parity: None
	Handshake: None
	Use Port For: Terminal Session
	Baud Rate :9600

9) Select the "Main Menu" botton with the left mouse button
to get back to the main menu.

10) Select the "X Server Parameters" button with the left mouse
button to get the X Server Parameters Menu.

Confirm the following factory settings:
	Retain X settings: No
	Backing Store: By Request (This could be changed to Auto When Mapped)
	Keyboard Type:	LEAVE IT ALONE
	DW Compatibility: Yes
	Permit Old X Bugs:	Yes
	Disable Error Popup:	NO

Change the following factory setting
	Virtual Term At Reset: None
to:
	Virtual Term At Reset: Serial

11) Select "Main Menu"

12) Select "Save Power On Values"

13) Select "Reset Server," or simply powercycle the X display.

The terminal will boot, and the Serial Session window will appear.

14) Now configure the modem.  Type in the string which appears
in the "MPCI Generic X Environment."

AT ~ &F S58=0 S50=6 S54=3 S55=3 &W

Follow this string with a [Return]

The modem will respond
OK

16) Now dial a properly configured Telebit modem on a host
with supports Xremote.  See the "MPCI Generic X Environment"
with regard to how to do this, we are not committed to helping
configure a foreign host.

ATDTxxxxxxx

Where xxxxxxx is the phone number of this machine.

You will get a CONNECT 9600 message when it connects.
If you get a CONNECT FAST message you have a PROBLEM, presumably
because you have not followed the above directions or because
you have not dialed a properly configured modem and host.

You will get the standard login prompt of the host, and might
possibly have to hit [Return] to elicit such a prompt.  It is
known that our machine, mpci.llnl.gov, does not require a [Return]
to generate the desired prompt.

9) Login as normal for a serial line.

10) If you have a .xinitrc file which is linked to your .xsession
file, or a copy of such a file which has been customized, you type
the command

xinitremote

and your standard MPCI Generic X Environment will come to life.  The
Led 1 will show the serial line grinding away during this time.

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

To shut down X you select "Exit X" as described in the "MPCI Generic
X Environment."  You then use ^D or "logout" for the normal serial
line logout, depending on the shell that you normally use.

Subject: 5: )   General Terminal Server settings

	In general, terminal server setup for running XRemote passed
	through a rs232 port should not have any mode that can cause the
	terminal server command prompt to become active.

	The rs232 port should also have all software flow control 
	disabled, but hardware flow control may be required to ensure
	that the terminal server port buffer is not execeded.

	Some terminal servers support a forwarding character and a forwarding
	timer.  Both of these parameters should be set to help performance.
	The forwarding timer should be set to "1" or the smallest allowable
	value. And, the forwarding character should be set to "~" or "126".

The following parameters are for a CISCO terminal server serial port, 
if the CISCO terminal server dose not have support for the XRemote 
protocol built in.


CISCO per port parameters

no escape-character
autohangup
dispatch-timeout 1
dispatch-character 126

----------------------

This is how to setup a Xyplex terminal server to "passthrough" Xremote. 


This means that Xremote is NOT running the terminal server but it 
is running on a host that a user can telnet to.


Set the Xyplex port to a passall mode with the following command:

	set port <N> default session mode passall

Then you must use a telnet to and login to the host. Then run xinitremote as
normal.

-----------------------------------------

HELP INFORMATION from XYPLEX:

SET PORT Subtopic? DEFAULT SESSION
        DEFAULT SESSION MODE [INTERACTIVE]
                             [PASTHRU]
                             [PASSALL]
                             [TRANSPARENT]

  INTERACTIVE For Telnet sessions, the terminal server will not attempt
                 to negotiate binary mode at session startup.
                 For LAT sessions, the terminal server will tell the remote
                 it is in INTERACTIVE mode.
                 Required for TN3270 sessions.

  PASTHRU   For Telnet sessions, the terminal server will attempt to
                 negotiate binary mode at session startup and use local
                 flow control.
                 For LAT sessions, the terminal server will tell the remote
                 it is in PASTHRU mode.
                 Switching characters are disabled.

  PASSALL   For Telnet sessions, the terminal server will attempt to
                 negotiate binary mode and also, disable flow control.
                 For LAT sessions, the terminal server will tell the remote
                 it is in PASSALL mode.
                 Switching characters and XON/XOFF flow control are disabled.

  TRANSPARENT  For Telnet sessions, the terminal server will act as a raw
                 TCP pipe, treating every byte as data. Telnet option
                 negotiation, Telnet commands, and flow control are not
                 interpreted.
                 For LAT sessions, the terminal server sets the mode to
                 PASSALL.

