D-Channel X.25

PAD SERVICE SIGNALS

The local DTE may receive service signals from the PAD in response to an issued PAD command or as the result of a packet or network action. Table 12-2 shows the service signals that may be transmitted to the local DTE by the PAD.

Table 12-2:PAD Service Signals

Command

Extension

Reason

 

 

 

*

 

PAD is in the PAD command state and the

 

 

user can issue a PAD command

 

 

 

ENGAGED

 

Response to PAD STATus command

 

 

 

FREE

 

Response to PAD STATus command

 

 

 

PAR

Parameter:

Response to set PAD command if one of the

 

value or

parameters to be set is invalid or response to

 

Parameter: INV

set and read command or read command

 

 

 

ERR

 

PAD command is in error

 

 

 

RESET

See PAD Reset

Resetting by the network or remote DTE

 

Service Signals

 

 

 

 

CLR

See PAD Clear

Clearing by the network or remote DTE

 

Service Signals

 

 

 

 

CLR

CONF

Confirmation of clearing either initiated by the

 

 

CLR PAD command or by the packet

 

 

 

CLR

DER

Restart on the network link or response to

 

 

packet virtual call request when the call

 

 

cannot be established

 

 

 

COM

 

Call connected in response to a PAD Select

 

 

command or the receipt of an incoming call

 

 

(connection based upon acceptance of

 

 

incoming call by the packet)

 

 

 

XXX

 

Line delete function performed for a printing

 

 

terminal

 

 

 

\

 

Character delete function performed for a

 

 

printing terminal

 

 

 

BS SP

 

Character delete function performed for a

BS

 

display terminal

 

 

 

CR LF

 

Acknowledgment of a PAD command such

 

 

as RESET or INT

 

 

 

12-14

UTA220/UTA220k

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Northern UTA220/UTA220k manual 2PAD Service Signals Command Extension Reason