Specifications

Data Structures
1.19 Unit Control Block (UCB)
Table 1–26 (Cont.) UCB Terminal Extension
Field Name Contents
UCB$B_TT_DELFF* Default line-feed fill.
UCB$B_TT_DEPARI* Default parity/character size.
UCB$B_TT_DETYPE* Default terminal type.
UCB$W_TT_DESIZE* Default line size.
UCB$W_TT_SPEED* Terminal line speed. This field is read and written by the class driver, and
read by the port driver. It contains the following byte fields:
UCB$B_TT_TSPEED Transmit speed
UCB$B_TT_RSPEED Receive speed
UCB$B_TT_CRFILL* Number of fill characters to be output for carriage return.
UCB$B_TT_LFFILL* Number of fill characters to be output for line feed.
UCB$B_TT_PARITY* Parity, frame and stop bit information to be set when the PORT_SET_LINE
service routine is called. This field is read and written by the class driver,
and read by the port driver. It contains the following bit fields:
UCB$V_TT_XXPARITY Reserved to Digital.
UCB$V_TT_DISPARERR Reserved to Digital.
UCB$V_TT_
USERFRAME
Reserved to Digital.
UCB$V_TT_LEN Two bits signifying character length (not
counting start, stop, and parity bits), as follows:
00
2
= 5 bits; 01
2
= 6 bits; 10
2
= 7 bits; and 11
2
= 8 bits.
UCB$V_TT_STOP Number of stop bits: clear if one stop bit; set if
two stop bits.
UCB$V_TT_PARTY Parity checking. This bit is set if parity
checking is enabled.
UCB$V_TT_ODD Parity type: clear if even parity; set if odd
parity.
UCB$L_TT_TYPAHD* Address of type-ahead buffer.
UCB$W_TT_CURSOR* Current cursor position.
UCB$B_TT_LINE* Current line position on page.
UCB$B_TT_LASTC* Last formatted output character.
UCB$W_TT_BSPLEN* Number of back spaces to output for non-ANSI terminals.
UCB$B_TT_FILL* Current fill character count.
UCB$B_TT_ESC* Current read escape syntax state.
UCB$B_TT_ESC_O* Current write escape syntax state.
UCB$B_TT_INTCNT* Number of characters in interrupt string.
UCB$W_TT_UNITBIT* Enable and disable modem control.
(continued on next page)
1–103