X25AM Programming Manual

ITI Applications

X25AM Programming Manual—527201-001

2-18

Disposition of Terminal Control Characters by ITI

When the terminal is in conversation mode, interrupt characters received from the

terminal indicate to ITI that something needs to be done with the application input

buffer and the character. For special line termination characters, see the description of

SETMODE 38 in Appendix A, Procedures Summary for X25AM. Table 2-6 shows the

effects of these characters.

If the data-forwarding character is a carriage return (CR), then the PAD forwards data

when a carriage return appears in the data. If the carriage return is followed by a

linefeed (LF) character, the LF character is not included in the data transmitted to ITI.

PAD parameter 13 distinguishes a CR from a CR followed by a LF. If the value is zero,

a CR/LF cannot be distinguished from CR. If the value is 4 (and if SETMODE 7 is 1),

then the LF is inserted if it is received by the PAD.

The Disposition of Framing Characters by ITI

When the terminal is in page mode, ITI removes framing characters from incoming

data blocks reassembled from packets. These framing characters include:

•

The leading SOH and trailing ETX LRC (nontext).

•

The leading STX sequence number and trailing ETX LRC (text).

Table 2-6. The Disposition of Terminal Characters by ITI

Interrupt Character Disposition Action

Backspace (BS) Delete preceding character from

buffer.

Continue placing characters in

buffer.

Line Cancel (CAN) Delete all data in buffer. Send @

CR/LF to terminal.

Continue placing characters in

buffer.

End Of File (EOF) Send EOF! CR/LF to terminal.

Delete EOF from buffer.

Transfer buffer to application and

return file error 1. READ

terminates.

Carriage Return (CR) Delete CR from buffer. Transfer buffer to application.

READ terminates.

Carriage Return/Line

Feed (CR/LF)

Delete CR and LF from buffer. Continue placing characters in

buffer.

All others Leave in buffer. Transfer buffer to application.

READ terminates.