Datapac (public packet-switching network)
Datapac is a Canada-wide, public packet-switching network operated by Telecom Canada. It allows access to computer systems from most major cities in North America and other countries at a lower cost than long distance. The network is call-based, providing virtual circuits between terminals. All you need is a terminal or a personal computer, a modem or an SL-1 data card and communications software.
When you wish to make long distance contact with a computer using Datapac, you first place a call to a local computer. A simple command to this computer tells it which main computer site you wish to contact. From then on, everything typed in at the terminal is forwarded to the desired computer, and all responses are sent back to the terminal. Telephone company charges are based upon the quantity of data transmitted, your location and connect time. For calls into McGill's MUSICA, you will be billed automatically on your Computing Centre account. If you wish to access MUSICB, or other campus systems which are Gandalf PACX connected, you must first make arrangements with the Computing Centre.
For the documentation that follows, please note the following definitions:
The XMUX is a Packet Assembler/Dissassembler (PAD) which allows a user to access packet switching networks (Datapac, TYMNET, Telenet, ...) from their asynchronous terminals. For a list of XMUX commands, see Appendix D.
The PACX is a data switch which allows a user to access various resources (computer system, library system, XMUX, . . .).
In the following, (CR) means that you should depress the enter key. Parity should be even. Note: Class 73 and DATAPAC can be used interchangeably.
1. On campus users can connect to McGill PACX using your normal procedure (Gandalf boxes (class 73), or SL-1 data card dial 8424). Note: Class 73 is not available for users coming through dial-in modem pool connections.
2. The PACX prompts with : "enter class"
Enter : "DATAPAC (CR)" (to connect to class 73)
The PACX prompts with : "class start"
Enter : "(CR) (CR)"
Now you are connected to the XMUX.
3. The XMUX responds with the following:
"GANDALF: Welcome to McGill XMUX Channel #
*"
Now you are ready to place a call.
4. From the XMUX, you can only place reverse-charges calls or NUI (Network User Identifier) calls, meaning that either the destination host must accept the charges, or you must charge the call to your own NUI. (To obtain a NUI, you should contact the Telecom Office.)
5. Place a call by entering a call request command. Examples of commonly used call request commands follow. For a detailed description of ALL the options available, refer to Appendix A.
a) To connect to an address on Datapac:
enter: "r-xxxxxxxx (CR)" (where r means a "reverse charge" call and xxxxxxxx is the address of the installation.
b) To place an international call:
enter: "r,p-1xxxxyyyyyyyy (CR)" (where p means "priority" call and is required for all international calls, xxxx is the DNIC, and yyyyyyyy is the network address of the installation)
c) To charge the call to a NUI:
enter: "Npswdcode,p-1xxxxyyyyyyyy (CR)" where pswd is the NUI password and code is the NUI code.
d) To access TYMNET:
enter:"@tymnet (CR)" (equivalent to r,p-13106, where 3106 is the TYMNET DNIC)
TYMNET responds with: "TYMNET : please log in :"
e) To access Telenet sites which have a user name:
enter: "@telenet (CR)" (instead of r,p-1311021200141, where 3110 is the Telenet DNIC and 21200141 is a Public Telenet location)
Telenet responds with: "User Name?"
At this point, you can access any site which has a user name.
6. To end your call, sign off from the host.
Then, if your connection to the host is not dropped,
enter: "CNTL P" (depress the Control key and P simultaneously)
The XMUX responds with the prompt "*"
enter: "clr"
The XMUX responds: "* GANDALF: Call cleared"
You are now ready to place another call.
7. To summarize:
enter class
-->73 (CR)
class start
-->(CR) (CR)
GANDALF: Welcome to McGill XMUX Channel #
*
-->Your call request (e.g., "@tymnet (CR)" or "r-82700294
(CR)")
-->logon to session
.
.
-->logoff from session
-->CNTL-P
*
-->clr (CR)
*
GANDALF: Call cleared
Dial the Datapac 3101 public dial access number where you are. These numbers are listed in the local telephone directory under "Datapac". Some numbers are provided at the end of this handout in Appendix D. There are special telephone numbers for 300, 1200 and 2400 baud service. If you are using 2400 baud you may go to step 3 otherwise do step 2.
2. Once the connection is established you should type one period ".(CR)" for 300 bps or two periods "..(CR)" for 1200 bps.
3. Datapac will respond with "DATAPAC: xxxx xxxx" which denotes your network address. You now have one minute to answer.
4. In order to access McGill, enter the McGill address 57400022 followed by a single "user data" character using the appropriate syntax for this user data. Note that user data is optional:
e.g., 57400022,R(CR) (public Datapac access user data syntax)
57400022(CR) (no user data)
Valid user data characters are:
A for MUSICA B for MUSICB R for PACX-attached equipment
Note that McGill does not accept collect calls with the "R" user data. You must use a NUI (Network User Identification) to charge your calls. (A NUI can be obtained from the Telecommunications Office.) McGill does accept reverse charges for calls made to MUSICA (a surcharge is added to your bills to cover these charges). Note that if you wish to access MUSICB, you must make arrangements with the Computing Centre.
5. The message "CALL CONNECTED" will appear.
If you omitted the "user data" character, you will be prompted for the system you want after entering a (CR) following the CALL CONNECTED message. Then you can begin your session. Note that "R" can not be entered at this point, "R" must be entered via user data.
6. If you used "R" as the "user data" character, you will then receive the following message:
"Channel #: Connected" (where "#" is a two-digit number)
Then press "CR" and you will receive the "enter class" message.
From this point you select the Gandalf class you wish.
7. Sign on to your code on the chosen system.
8. When you sign off from your code, you will get the message:
DATAPAC: CALL CLEARED
9. To summarize:
-->Dial Datapac
-->. (CR) or .. (CR)
DATAPAC: xxxx xxxx
-->57400022,x (CR)
CALL CONNECTED
-->(CR) and/or log on to session
.
.
-->log off from session
DATAPAC CALL CLEARED
1. Dial the TYMNET public dial access number in the city where you are located. Some numbers are provided at the end of this handout in Appendix D.
2. Once the connection is established you should type (lower case) "a(CR)".
This will return a "login" message.
3. In order to access Datapac and McGill enter:
DPAC;302057400022:x(CR)
where "x" is user data as described above.
TYMNET will prompt you with the message "DATAPAC: call connected via xxx:". Press "(CR)" to select the McGill system you wish to connect to.
1. Dial the Telenet public dial access number for the city where you are located. Some numbers are provided at the end of this handout in Appendix D.
2. Once the connection is established, you should type "U4 (CR)".
Telenet answers with: "Telenet
xxx xxx
Terminal ="
enter: "(CR)"
You will then see the Telenet prompt "@".
3. In order to access Datapac and McGill, enter:
C 0 3020 57400022 (CR)
Telenet will answer with: "3020 57400022 connected". Press "(CR)" to select the McGill system you wish to connect to.
Different options (priority packet sizes, NUIs, user data characters, etc.) may be specified when making a call on the XMUX. The syntax is described below. Those items in curly brackets "{ }" are optional. Note that the dash/hyphen preceding the address is required.
<charging>{,<option>} - <address> {<data mark><data>}
<charging>: This option specifies the method of charging for the call and is required. Choose one of the following:
"R" : This indicates that reverse charging should be used.
"Nxxxxxyyyyyyyy": Charge the call to NUI yyyyyyyy with password xxxxxxxx. For security the NUI will not appear as it is typed.
<option>: This item is optional. If more than one of the following options are selected they must be separated by a comma (",").
"P" : This specifies priority packet sizes. (Required
for international calls.)
"D<number>" : The number following the D is bits
per second.
"1<number>" : The number following the 1 specifies
a DNIC.
<address>: Any string of digits
<data mark>:
"D" : to include your user data
"P" : to include your user data which will not appear
when typed
<data>: Your user data or password (up to 12 characters)
r-80473029 Reverse charged call to destination address 8047329
r-20400354dtso Call 20400344 and access TSO
r,p,13110-212001416 Priority call using DNIC 3110 to address 21200141
Nmynuipz8975554-57400022 Charge the call to nui z8975554 with password
mynuip to access 57400022 (McGill's address)
Nmynuipz897554,p-1311090900406 Priority call to access a user on Telnet
r,p-80417347psecret priority call to address 80417347 using password
secret (which will not appear on the screen when typed)
1. Normally a user enters a command, and awaits the response from the command before entering the next command. When the system is accessed via Datapac, up to four commands may be entered before the response from the first command has been received. If the number of 'Type Ahead' commands, as this is called, is exceeded, the network responds with a 'beep', and subsequent input is ignored. Any user entering a large amount of data will find that 'Type Ahead' will give the appearance of instantaneous response. At any time, a BREAK or INTERRUPT may be entered. This is immediately sent to the system.
2. Datapac has better line error detection than normal access. When an error is detected, the message
DATAPAC: RE-ENTER
appears as soon as the erroneous character is entered.
In this case the line should be re-entered. If the message
DATAPAC: INPUT DATA LOST
appears, the input line was over 256 characters long when the error was detected and the first 128 characters have already been transmitted. Since such long input lines are rare, this should not be a problem.
3. When accessing MUSIC through Datapac, users of video display terminals such as the Volker Craig 404 should take note of special handling of "MORE" mode. Normally, when you are signed-on with a paging controlled terminal type such as VC404, MUSIC will halt output to the terminal when the screen is full and place "MORE..." at the bottom right hand corner of the screen. When you press the return key, MUSIC continues the output.
This is not true when you are using Datapac. The only accepted response to MORE mode is the BREAK character. Anything else (including the RETURN key) is ignored by Datapac. However, hitting the BREAK key in response to MORE... is valid under all circumstances and will not put you into BREAK mode.
4. Data transfer may not work properly with Datapac. Binary (8-bit) output will not work with Datapac.
All messages from Datapac are of the format
DATAPAC:
<text> where <text> may be:
1) xxx xxxx - seven digits of user's address displayed when connection to the network is established.
2) INVALID ADDRESS - displayed when the user enters the destination address with the wrong syntax.
3) CALL CONNECTED - displayed when the user successfully establishes connection.
4) RE-ENTER - displayed when an error has been detected during input.
5) INPUT DATA LOST - same as 4, but the first 128 characters have been sent. Line delete (left square bracket) must be entered.
6) CALL CLEARED <cause> - when a call is terminated normally, i.e., when you log off or when the McGill system is not functional, no <cause> is given. Otherwise, <cause> may be:
a) DESTINATION BUSY - destination cannot be reached because all the McGill ports are engaged.
b) TEMPORARY NETWORK PROBLEM - as implied, try again. This may also indicate that an invalid international address has been requested. If the problem persists verify that the international address is valid before calling Computing Centre Operations at (514) 398-3699.
c) DESTINATION NOT RESPONDING - this normally means that the system is down.
d) ADDRESS NOT FOUND - destination address non-existent.
e) LOCAL PROCEDURE ERROR - system problem. Please report it to Operations.
7) RESET <cause> - This is a system problem which should be reported to Operations. One or two input or output lines may have been lost if this message appears, but the call remains connected.
8) MCGILL CANNOT CONNECT TO DATAPAC - This error usually means that the lines are busy and you should attempt to connect once again or that you have mistyped the network address. If the problem persists, contact Operations at (514) 398-3699.
City Area Code 300 Baud 1200 Baud 2400 Baud Montreal 514 878-0450 878-0640 875-9470 Ottawa 613 567-9100 567-9300 567-4431 Quebec City 418 647-4690 647-2691 647-3181 Sherbrooke 819 566-2770 566-2990 Toronto 416 868-4000 868-4100 979-1619
For a more complete list of Datapac phone numbers: Dial a DATAPAC public telephone number. After the prompt, "DATAPAC: xxxx xxxx", enter "92100086".
City Area Code 300, 1200 Baud 2400 Baud
Albany 518 465-8444 465-8632
New York 212 741-8100 645-0560
741-4950
620-6000
For a more complete list of Telenet telephone numbers: Enter the command "@telenet" on the XMUX. (User name: "phones" and password: "phones").
City Area Code 300, 1200 Baud 2400 Baud Albany 518 458-8300 458-9724 New York 212 934-4700 809-9660
For a more complete list of TYMNET telephone numbers: Enter the command "@tymnet" on the XMUX. (login: "information").
Once you are connected to the XMUX, you may issue commands to the XMUX directly. Some commands may be issued at any time, some may be entered only when a call is NOT in progress, and others only when a call IS in progress.
1) PAD commmand that may be issued at any time:
i) STAT: The status PAD command signal is used to request status information on whether a call is connected. The reply will either be "connected to" or "free".
2) PAD command which may be issued only when a call is not connected:
i) CALL: This command is used to retry the previous call setup using the same addresses, facilities, and call data.
ii) USER <nui>: This command will set the Network User Identifier to be charged for all subsequent call attempts. To cancel an active NUI enter a null nui following USER. Enter USER? to find if a NUI is active.
3) PAD commands that may be issued only when a call is in progress. (These commands may only be issued after you have entered a CNTL-P):
i) CLR: This command will clear your call.
ii) INT: The interrupt PAD command signal will transmit an interrupt request packet.
iii) INTD: The interrupt and discard command transmits both an interrupt request packet and an "Indication of Break" that will discard output.
After entering CNTL-P followed by one of these commands, you will see the XMUX prompt ("*"). Enter another PAD command or press (CR) to return to the call in progress.
By Modem:
398-8111: ASCII 300 2400
398-8711 : ASCII 1200 2400 MNP5
398-8311 : ASCII 9600 MNP5
By SL-1 Data Card:
8424