Page A-3APPENDIX A — INTERFACING XEROX PRINTERS
The OPTIMA provides several methods that allow SCS and XES
documents to coexist in the same environment.
Coexistence
In order to eliminate the formatting conflicts that can arise when using
XES commands to control document formatting, the OPTIMA provides
two special modes of operation, one called PFS (Programmable Function
String) suppression mode, and the other called FF (Form Feed)
suppression mode. These two modes of operation can act independently or
in unison.
When the OPTIMA receives SCS commands from the host system, it sends
PFSs to the printer to simulate the behavior of the IBM printer it is
emulating. PFSs contain the XES commands used to control the printer.
When the OPTIMA is in PFS suppression mode, it continues to receive
and interpret SCS commands from the host system; however, it does not
send the required PFSs to the printer. For the duration of PFS suppression
mode, the system effectively loses the ability to control document
formatting, allowing full control of the formatting via XES commands.
When PFS suppression is active, the only PFSs sent to the printer are CR>,
LF> and FF> PFSs.
When the OPTIMA is in FF suppression mode, any Form Feed characters
received from the host system are ignored. This allows the user to fit an
large number of XES commands on one physical page at the printer, even
though the system thinks it is printing multiple pages.
The OPTIMA provides three general methods for initiating and
terminating PFS and FF suppression modes. Two of these methods use
embedded triggers in the data stream to delimit the section of the data
stream where the PFS or FF suppression modes are to be active. Another
method the OPTIMA provides for initiating and terminating PFS and FF
suppression modes is the use of separate addresses.
Separate Addresses
Of the three methods used to control PFS and FF suppression, the use of
separate addresses is probably the simplest. The idea behind the separate
addresses method is that one twinax address can be configured on the
OPTIMA to have PFS and/or FF suppression modes constantly active, and
another address can be configured to have them inactive.