User`s guide

459
Example
CALL R,G12,NMYNUI-56512120DHello
places a call to address 56512120 using reverse charging and specifying Closed User Group
12. The string “MYNUI” is your Network User Identity and the string “Hello” appears in the
user data field of the call packet.
Note:
The particular facilities that are available will vary between X.25 service providers.
If a CALL command is issued without the address parameter, it is assumed that you wish to
go back on-line to a previously established call (having used the PAD recall facility to
temporarily return to the PAD> prompt).
Fast select (ISDN B-channel only)
When the standard Fast select facility is requested using the “F” facility code, the call packet
generated by the CALL command is extended to allow the inclusion of up to 124 bytes of
user data. For example:
CALL F-1234567890DThis DATA sent with call packet
would cause an X.25 CALL packet to be sent using the Fast select facility including the
message “This DATA sent with call packet” (the Carriage Return used to enter the command
is not transmitted). Without the inclusion of the Fast select facility code, only the first 12
characters would be sent.
When a Fast select CALL has been made the PAD accepts an extended format response from
the called address. This response, consisting of up to 124 bytes of user data, may be
appended to the returning call accepted or call clear packet. When one of these packets is
received, the user data is extracted and passed from the PAD to the terminal immediately
prior to the “CLR DTE . . .” message in the case of a call clear packet or “CON COM”
message in case of a call accepted packet.
When a restricted response Fast select call has been made using the Q facility code, the call
packet indicates that a full connection is not required so that any response to the user data
in the CALL packet should be returned in a call clear packet.
When the PAD receives an incoming call specifying Fast select, the call is indicated to the
terminal in the normal way. For example:
IC 1234567890 FAC: Q,W:2 COM
would indicate that an incoming call had been received requesting Restricted response fast
select and a window size of 2. The user (or system) then has 15 seconds in which to pass
up to 124 bytes of data to the PAD to be included in the clear indication packet that is sent
in response to the call.
The PAD does NOT differentiate between standard and restricted response Fast select on
incoming calls and, consequently, will always respond with a clear indication.