As per Relevance of the word indicate, we have this rfc below:
Network Working Group P.
Request for Comments: 1205 IBM
February 1991
5250 Telnet
Status of this
This RFC is being distributed in order to document the interface
the IBM 5250 Telnet implementation. This information is
provided for hosts on the Internet that want to support the 5250
station data stream within the Telnet protocol. This memo
information for the Internet community. It does not specify
standard. Distribution of this memo is unlimited
1.
This RFC describes the interface to the IBM 5250
implementation. The purpose of this memo is to describe the
of the interface so that a person wanting to implement a
Telnet which emulates an IBM 5250 work station would be able to
so. This memo does not describe all of the 5250 commands, aid codes
and other information specific to the 5250 data stream.
information is contained in the IBM 5250 Information Display System
Functions Reference Manual, IBM publication number SA21-9247.
Corrections and additions to this manual are documented in this
in section 5.
2. Telnet
No new Telnet options are defined for 5250 mode of operation
However, to enable 5250 mode, both the client and server must
to at least support the Binary, End-Of-Record (EOR), and Terminal
Type Telnet options. The complete list of 5250 terminal types
maintained in the Assigned Numbers RFC and includes the following
IBM-5555-C01 24 x 80 Double-Byte Character Set color
IBM-5555-B01 24 x 80 Double-Byte Character Set (DBCS
IBM-3477-FC 27 x 132 color
IBM-3477-FG 27 x 132 monochrome
IBM-3180-2 27 x 132 monochrome
IBM-3179-2 24 x 80 color
IBM-3196-A1 24 x 80 monochrome
IBM-5292-2 24 x 80 color
IBM-5291-1 24 x 80 monochrome
IBM-5251-11 24 x 80 monochrome
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RFC 1205 5250 Telnet Interface February 1991
An example of a typical negotiation process to establish 5250 mode
operation is shown below. In this example, the server initiates
negotiation by sending the DO TERMINAL-TYPE request
Server: IAC DO TERMINAL-
Client: IAC WILL TERMINAL-
Server: IAC SB TERMINAL-TYPE SEND IAC
Client: IAC SB TERMINAL-TYPE IS IBM-5251-11 IAC
(The client has specified its terminal-type is an IBM-5251-11)
Server: IAC DO END-OF-
Client: IAC WILL END-OF-
Server: IAC WILL END-OF-
Client: IAC DO END-OF-
(The server and client have both agreed to transmit EORs
Server: IAC DO TRANSMIT-
Client: IAC WILL TRANSMIT-
Server: IAC WILL TRANSMIT-
Client: IAC DO TRANSMIT-
(The server and client have both agreed to binary transmission
3. Data Stream
The actual data stream that is exchanged between the client
server is composed of a header followed by the 5250 work station
stream. For information about the 5250 work station data
refer to the IBM 5250 Information Display System, Functions
Manual (SA21-9247). The header which prefixes the 5250 data
was originally designed for the 5250 Display Station Pass-
(DSPT) application. 5250 DSPT is an application similar to
which runs on the IBM AS/400, System/36, and System/38 over an
network. This header is designed to be variable in length and
composed of two parts. The first, fixed part is always 6 octets
and has the following format
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Logical Record Length | Record Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Logical Record Length: 16
This field indicates the length, in octets, of this logical
including the header length. The length is calculated
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RFC 1205 5250 Telnet Interface February 1991
doubling any IAC characters in the data stream. The length
not include the that is appended to the end of the
stream to mark the end of this logical record. The length
specified with the most significant octet first. For example,
length of 36 (decimal) would be specified as '0024'X
Record Type: 16
This field indicates the SNA record type. It should always be
to '12A0'X to indicate the General Data Stream (GDS) record type
Reserved: 16
This field is currently not used
The second part of the header is designed to be variable in length
The length of this variable part is specified in the first octet
Currently this portion of the header will always be 4 octets long
has the following format
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |E|A| | | |S|T|H| | |
| Var Hdr Len |R|T| | | |R|R|L| | Opcode |
| |R|N| | | |Q|Q|P| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Var Hdr Len: 8
The length, in octets, of the variable portion of the header
Currently this is always '04'X
Flags: 16
Bit 0: ERR This bit is set to indicate a data
output error. The negative response
is sent as data following the opcode field
Bit 1: ATN This bit is set to indicate that the 5250
attention key was pressed
Bits 2-4: * These bits are reserved (set to zero).
Bit 5: SRQ This bit is set to indicate that the 5250
System Request key was pressed
Bit 6: TRQ This bit is set to indicate that the 5250
Test Request key was pressed
Bit 7: HLP This bit is set to indicate the Help
Error State function. The error code
sent as data following the header and
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RFC 1205 5250 Telnet Interface February 1991
a four digit packed decimal number.
example, an error code of '0005'X
the operator attempted to type in an area
the display that is not enabled for input
Bits 8-15: * These bits are reserved (set to zero).
Opcode: 8
This field contains the operation code. It is set to indicate
type of operation requested by the sender. The following are
valid values
'00'X: No
'01'X: Invite
'02'X: Output
'03'X: Put/Get
'04'X: Save Screen
'05'X: Restore Screen
'06'X: Read Immediate
'07'X:
'08'X: Read Screen
'09'X:
'0A'X: Cancel Invite
'0B'X: Turn On Message
'0C'X: Turn Off Message
The actual 5250 work station data stream will immediately follow
opcode field in the header and will be terminated by the
pair. For some operations the header will be immediately followed
an without any 5250 work station data stream in between
For example, the following request to turn on the message light
be sent by the server
000A 12A0 0000 0400 000B
| | | | | | |
| | | | | | End Of Record
| | | | | |
| | | | | Opcode = Turn On Message Light ('0B'X
| | | | |
| | | | Flags = '0000'
| | | |
| | | Variable Header Length = '04'
| | |
| | Reserved - Set to '0000'
| |
| Record Type = General Data Stream ('12A0'X
|
Logical Record Length = '000A'X for this
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RFC 1205 5250 Telnet Interface February 1991
In this example the requested operation is indicated by the
and there is no associated work station data stream
4. Data Flow
The following examples illustrate the flow of data between the
and server for some of the more common operations. These
are intended to show the order in which the logical records are
between the client and server and the content of those records.
hex representation of the records which are exchanged between
client and server is shown. The way in which a client implements
various operations will differ between implementations and
details are not discussed here. In these examples, when the value
a field is dependent on the length of the screen data for
particular logical record, it will be represented as 'LLLL'.
4.1 Query Device
A Query command may be sent by the server system in order
determine the attributes of the device it is talking to. When
client receives a Query command, it must send the Query Reply back
the server. See section 5 for a complete description of the
for the Query command and Query Reply
Server: Sends Write Structured 001112A0 00000400 000304F3 0005D970
Field Query command. 00
Client: Responds with a Query 004712A0 00000400 00000000 88003AD
Reply, in this case, 70800600 01030000 00000000 00000000
for a 3180-2. 00000000 00000001 F3F1F8F0 F0F0F202
00000061 50000100 00000018 11000000
00000000 000000FF
4.2 Cancel Invite
The server will send a Cancel Invite when it needs to reverse
normal flow direction. When a client receives a Cancel Invite,
should reply with a Cancel Invite and not send any user data
the server has once again "invited" the work station. A work
is said to be "invited" when the server has sent a read command
the client. The Cancel Invite flow is as follows
Server: Sends header with the 000A12A0 00000400 000
Opcode = Cancel Invite
Client: Sends header with the 000A12A0 00000400 000
Opcode = Cancel
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RFC 1205 5250 Telnet Interface February 1991
to indicate that
work station is
longer invited
4.3 System Request
The 5250 System Request operation is invoked when a client wants
interrupt the server job to perform some function. The
scenario would be for a user to press the system request key,
whatever key is mapped to a system request key, which would cause
client Telnet to initiate the following flow
Client: Sends header with the 000A12A0 00000404 0000
System Request bit set
Note: It is possible for a client to include user data in
record following the header. This data would be interpreted by
server as an option to be selected from the system request menu.
this were the case, the server would not send the system request
and the flow would continue based on the option selected. For
example, the client does not send any user data and the flow
continue as follows
Server: Sends header with the 000A12A0 00000400 000
Opcode = Cancel Invite
Client: Sends header with the 000A12A0 00000400 000
Opcode = Cancel
to indicate that
work station is
longer invited
Server: Sends Save (Immediate) 000C12A0 00000400 00040402
command
Opcode = Save Screen
Client: Sends the screen image LLLL12A0 00000400 00040412
to be saved.
Server: Sends System Request LLLL12A0 00000400 0003
menu with
Opcode = Put/Get
Client: Sends User Input to LLLL12A0 00000400 0000
the Sys Req menu.
Note: What happens next will depend on the System Request
selected by the user. After any System Request processing
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RFC 1205 5250 Telnet Interface February 1991
completed, the server will continue with the following
operation
Server: Sends the saved LLLL12A0 00000400 00050412
screen to be restored,
Opcode = Restore Screen
(No reply is necessary from the client
Server: Sends Read Modified 000E12A0 00000400 00010452 0000
Data Tag (MDT) command
opcode = Invite
At this point the client would "invite" the workstation and enter
state that it was in prior to the System Request key being hit
5. 5250 Data Stream
This section is intended to be used as an addendum to the IBM 5250
Information Display System, Functions Reference Manual.
here are enhancements to the 5250 data stream which are not
documented in the current version of that manual. The
version of that manual at the time of this writing has the
publication number SA21-9247-6. Also described in this section
corrections to erroneous information contained in SA21-9247-6.
Listed below are the specific corrections and enhancements, with
approximate page number reference to the above manual
5.1 Errors or Inconsistencies in SA21-9247-6
The Insert Cursor (IC) order on pages 2-136 and 2-137 is
listed with a value of Hex 03; the correct value is Hex 13.
On page 2-137, the listed "Restrictions" for the Insert Cursor
Repeat to Address, and Set Buffer Address orders should be updated
describe how Row and Column values must be valid for the
display screen size (either 24 x 80 or 27 x 132).
5.2 Enhancements to Existing 5250 Data Stream Commands/
A new flag is added to the second byte of the Control Character
page 2-40. This flag is used to specify whether the cursor should
moved or not moved at the end of the Write to Display processing
Bit 1 of the second byte, which was previously reserved, will now
used for this flag. If bit 1 is a 0, the cursor continues to
moved to the system IC address on a Lock-to-Unlock
transition. If bit 1 is a 1, the cursor is not moved
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RFC 1205 5250 Telnet Interface February 1991
A new Field Control Word (FCW) will be added on page 2-65 to
an entry field contains transparent data. This means the entry
contents are sent from the display screen directly to the host
read time with no formatting. Therefore, an entry field can
any values (Hex 00 to Hex FF). A transparent field is indicated by
Hex 84xx FCW, where xx is any value. Note: unpredictable
will occur if a field is defined as both signed numeric and
transparent field
The Read Immediate, Read Input Fields, and Read MDT Fields
have been enhanced to include support for transparent fields (
2-5). If a transparent FCW is found for an input field, the
data is not formatted (for example, nulls are not converted
blanks).
The restriction listed for the Set Buffer Address (SBA) order (
2-138) on the column address equal to zero is no longer always
case. A reference to Start of Field (SF) row 1/column 1
support should be made. A note should be added in SF to describe
1/Column 1 field support. A Row 1/Column 1 field is defined by a
of row 1/column 0, followed by an SF. For a Row 1/Column 1
field, the first input-capable position is row 1/column 1. If the
defines an input field, the screen attribute is not allowed to
nondisplay. Writing of the screen attribute is suppressed for a
1/Column 1 field and the attribute discarded
5.3 New 5250 Data Stream Commands/
The Read MDT Fields Alternate input command has been added. It
the same as the Read MDT Fields command except
- The command is indicated by a X'82'
- Leading and embedded nulls within the field remain as
The Read MDT Fields Immediate Alternate input command has been added
It is the same as the Read MDT Fields Alternate command except
- The command is indicated by a X'83'
- The command is an immediate read command like Read Immediate
therefore, no control characters follow the command byte
field data is returned immediately, and the aid code is X'00'.
The Move Cursor order (MC) has been added (page 2-137). The MC
moves the cursor to the location specified by the two bytes
the order. Byte 1 gives the row address and byte 2 gives the
address. The MC order is useful when the cursor is to be
without affecting the system IC address. The MC order is
by the Write to Display control character values including the "
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RFC 1205 5250 Telnet Interface February 1991
Cursor" flag (CC1 bit 1). If more than one MC or IC are found in
data stream, the cursor will move to the address specified in
last MC or IC
Restrictions
A parameter error will be posted when
- There are fewer then two bytes following the order
- The row address is zero or greater than the number
rows on the display screen
- The column address is zero or greater than the number
columns on the display screen
Format
Move Cursor Order Byte 1 Byte 2
X'14' Row Address Column
Results
The address specified by the MC order is used to move
cursor when the Write to Display is completed
The Transparent Data order (TD) has been added (page 2-137). The
order is followed by two length bytes and transparent data.
transparent data is written to the display screen at the
display address; any values (Hex 00 to Hex FF) are allowed in
transparent data. All length values are valid as long as the end
the display screen is not overwritten
Restrictions
A parameter error will be posted when
- There are fewer then two bytes following the order
- There are fewer bytes in the data stream then specified in
length field
- Attempting to write beyond the end of the display screen
Format
TD Order Bytes 1 and 2 Bytes 3 to ?
X'10' Length of transparent Transparent
data (not
length bytes
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RFC 1205 5250 Telnet Interface February 1991
Results
The transparent data is written to the display
The Query command is a new input command (page 2-5) and is used
the server to obtain information on the functional capabilities
the client 5250 display. When the client receives a Query command
the client sends a Query Reply describing its capabilities back
the server
The Query command must follow an Escape ('04'X) and Write
Field command ('F3'X). The format of the Query command is
follows
Byte Value
====== ======= ========================
0-1 X'0005' Length of
2 X'D9' Command
3 X'70' Command Type -
4 X'00' Flag
Bit 0: B'0' - Query
Bit 1-7: - Reserved (set to zero
The format of the Query Reply is as follows
Byte Value
===== ======== ===================================
0-1 X'0000' Cursor Row/Column (set to zero
2 X'88' Inbound Write Structured Field
3-4 X'003A' Length of Query
5 X'D9' Command
6 X'70' Command Type -
7 X'80' Flag
Bit 0: B'1' - Query
Bit 1-7: - Reserved (set to zero
8-9 Controller Hardware
X'0001' - Local Twinax
X'0061' - Local ASCII
X'0101' - SDLC/X.21/X.25 Twinax
(5394 emulating a 5294)
X'0103' - SDLC/X.21/X.25 Twinax Controller (5394)
X'0200' - PC DOS non-DBCS
X'0300' - OS/2 non-DBCS
X'0400' - PC DOS DBCS
X'0500' - OS/2 DBCS
X'0600' - Other WSF or any other 5250
10-12 Controller Code
X'010300' - For example, Version 1 Rel 3.0
13-28 X'00' Reserved (set to zero
Chmielewski [Page 10]
RFC 1205 5250 Telnet Interface February 1991
29 Device
X'01' - 5250 Display or 5250
30-33 C'cccc' Device Type (e.g. 3180 for 3180 Mod 2)
34-36 C'ccc' Device Model (e.g. 002 for 3180 Mod 2)
37 Keyboard
X'02' - Standard
X'82' - G
38 X'00' Extended Keyboard
39 X'00'
40-43 X'xxxxxxxx' Display Serial
44-45 Maximum number of input
X'0100' - Typically = 256 input
46-48 X'00' Reserved (set to zero
49-53 Controller/Display
Bit 0-1: B'00' - No Row 1/Col 1
B'01' - Row 1/Col 1
Bit 2: B'0' - No Read MDT Alternate Command
B'1' - Read MDT Alternate Command
Bit 3: B'0' - Display does not have PA1/PA2
B'1' - Display does have PA1/PA2
Bit 4: B'0' - Display does not have PA3
B'1' - Display does have PA3
Bit 5: B'0' - Display does not have Cursor Select
B'1' - Display does have Cursor Select
Bit 6: B'0' - Display does not have Move Cursor Order
B'1' - Display does have Move Cursor Order
Bit 7: B'0' - No Read MDT Immediate Alt Command
B'1' - Read MDT Immediate Alt Command
50
Bit 0-3: B'0001' - 24 x 80 Screen
B'0011' - Capable of 24 x 80 and 27 x 132
Bit 4: B'0' - No light pen
B'1' - Light pen
Bit 5: B'0' - No Mag Stripe Reader
B'1' - Mag Stripe Reader
Bit 6-7: B'00' - Mono
B'01' - 5292/3179 style color, including color
51 X'00' -
52
Bit 0-2: B'000' - No Double Byte Character Set (DBCS
B'001' - Presentation screen DBCS capability
Bit 3-7: B'00000' -
53
Bit 0-2: B'000' - No graphics
B'001' - 5292-2 style
Bit 3-7: B'00000' -
54-60 X'00' Reserved (set to zero
Chmielewski [Page 11]
RFC 1205 5250 Telnet Interface February 1991
6.
1. IBM, "IBM 5250 Information Display System,
Reference Manual", SA21-9247-6, March 1987.
2. Postel, J. and J. Reynolds, "Telnet Protocol Specification",
RFC 854, USC/Information Sciences Institute, May 1983.
3. Postel, J. and J. Reynolds, "Telnet Option Specifications",
RFC 855, USC/Information Sciences Institute, May 1983.
4. Postel, J. and J. Reynolds, "Telnet Binary Transmission",
RFC 856, USC/Information Sciences Institute, May 1983.
5. VanBokkeln, J., "Telnet Terminal-Type Option", RFC 1091,
FTP Software, Inc., February 1989.
6. Postel, J. and J. Reynolds, "Telnet End of Record Option",
RFC 885, USC/Information Sciences Institute, December 1983.
Security
Security issues are not discussed in this memo
Author's
Paul
IBM
Highway 52 and 37 Street North
Rochester, Minnesota 55901
Phone: (507) 253-6315
EMail: paulc@rchland.iinus1.ibm.
Chmielewski [Page 12]
if you see any problems within the linking, don't worry be happy,
this is version 0.1 of the Relevance System and you gotta expect some crappy subroutines sometimes,
just be content we did not write this in Java, which would have made this "bigger and better" HAHAHHA.
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