Olivetti PR 4 - Main Differences between the Printer Models; Precaution on Receiving Status from the Printer

Printer features 1-21
Main differences between the printer models
The printer model with the RS-232 serial interface can emulate the Epson printers TM-950
and TM-U950.
The printer model with the IEEE 1284 Nibble/Byte mode parallel interface can emulate the
Epson printer TM-U950P. This printer model has:
• a specific interface cable supplied with the machine
• specific command codes (see the chapter "Epson TM-U950P commands")
• specific via console setup (see the section "Parameters - for printers with parallel
interface")
• an IEEE 1284 Nibble/Byte mode printer status transmission (see the next section entitled
"Precaution on receiving status from the printer").
Precaution on receiving status from the printer
The printer status transmission is available by using the both-way communication facility in
the Nibble /Byte mode, in accordance with the IEEE 1284 mode.
The following precautions must be taken for receiving the status from the printer:
• The allowable capacity of the printer’s internal buffer is 100 bytes. Status signal
exceeding this capacity will be discarded. To prevent possible loss of status data, the host
should always be ready for data reception (reverse mode).
• When ASB is issued, the host should be in the wait state for data reception (reverse idle
mode). When this state is not available, the host should enter the reverse mode to always
monitor the presence of data
• When ASB is issued, presence should be given to the ASB status for transmission over
the other status signals. Any accumulated ASB status signals left for transmission from
the last to the newest ASB status transmission should be transmitted together at one time
as one ASB status showing the change has been made, followed by the last ASB status.
Example: In the normal (wait) state, the ASB status is configured as follows:
0000 0000 0000 0000 0000 0000 0000 0000
When the following sequence of operations is performed , near end detection, cover open,
cover closed, the following pieces of data are accumulated.
1
st
status 2
nd
status 3
rd
status 4
th
status
1 0000 0000 0000 0000 0000 0011 0000 0000 Near end
detection
2 0010 1000 0000 0000 0000 0011 0000 0000 Cover open
3 0000 0000 0000 0000 0000 0011 0000 0000 Cover closed