HP 262SA - Permanent Block Mode; Handshake Priority

Block Data Transfer
Status
NONE
= GH
and Ec d: DCI = --G
Transmit NONE
= H( G + BD)
function
DCI
= --G( --B + --D ) = --(G+BD)
key:
DC2
= --H( G +
BD)
Modify
NONE
= --G + H
modes:
DCI
=0
DC2
= (--H)(G)
Notes: 1.
Permanent Block mode (multipoint datacomm) is equivalent to
G=H=I.
2. Handshaking for modify modes (Line Modify and Modify All), for this
terminal, is different from previous 262X terminals.
Permanent Block Mode
When the terminal is configured for HP multipoint datacomm operation, it is in a mode
referred to as cCpermanent Block mode" and the effective settings of the InhHndShk(G) and
I nh DC2 (H) straps are both cCYe 5", regardless of their settings in the configuration menu. In
permanent Block mode, there is no handshaking for any data transfers.
Handshake Priority
When handshaking other than cC
none
"
is in effect, and during receive mode of a half-duplex (e.g.
HP multipoint) datacomm configuration, more than one status request or other form ofblock
transfer may be pending while waiting on the completion ofa handshake. In this situation,
there is a prioritization of the responses rather than a first-in, first-out arrangement. The
priority list is as follows:
DC2 for
DCI/DC2/DCl handshake
Primary status
Secondary status
Device status
Cursor sense (absolute or relative)
User-defined function
key of cCT" or cCN" type
-,1:1, or send display (Ec d) Command completion status code (S, F, or U) Terminal ID,
terminal features, or graphics status
The priority list is implemented by an internal queue. Only one request response is sent for
each handshake completed. For device status, cursor sense, function key, and command
completion code status transfers, there may be more than one request before the handshaking
is done to allow the resulting transfer to take place.
9-5