X25AM Programming Manual
ITI Applications
X25AM Programming Manual—527201-001
2-10
PAD Parameters
ITI issues three kinds of control packets. They perform the following tasks: 
When the application clears a call as a result of issuing a CONTROL 12, ITI sends an 
Invitation To Clear to the PAD. Any operations that are in progress (such as a data 
transfer) are allowed to complete normally. The call is cleared by the remote device. 
When a call is cleared with CLOSE, ITI sends a Clear to the PAD. Any operations in 
progress are aborted.
PAD Response Packets
The PAD issues three kinds of response packets that are recognized by ITI. They 
perform the following tasks:
•
BREAK. The terminal operator has pressed the BREAK key.
•
ERROR. Something was wrong with a PAD message. Clear the call.
•
READ. Response of the PAD parameter value.
Any other response packet type is discarded and ignored by ITI.
PAD Parameters 
Both the PAD and the application must define the terminal that they are accessing with 
the same operating characteristics (for example, 80 characters per line). PAD 
operation is based on Recommendation X.3 that specifies the parameters that 
describe these operating characteristics.
These parameters are set to a standard configuration each time a virtual call (SVC) is 
established. Regardless of whether the call is initiated or accepted by ITI, ITI sends a 
SET command to the PAD. This initial PAD configuration can be specified by the 
operator with SCF or can be a default configuration that depends on the SCF 
subdevice attribute REMOTENET.
Default parameter sets have an internal and an external format. ITI constructs the 
internal format. ITI also translates the internal format to the external format. The 
external format is the one sent to the PAD.
You can modify the parameter values programmatically with the DSM SPI program or 
interactively with SCF.
Some file-system procedures can cause ITI to send SET PAD PARAMETER 
commands that alter only a specific parameter. SETMODE 20, for example, which 
•
SET  Set PAD configuration parameters.
•
READ Read PAD.
•
INVITATION TO CLEAR Request PAD to initiate a Clear Call when the PAD has 
finished all operations.
Note. If you choose to specify some PAD parameters, you must specify all standard and 
network-specific parameters (not just those being modified).










