GCS_PDFEXT[CV G>] This variable can be set in FAXFACTS.CFG, or a template passed to GCSINGLE on converting TIF to PDF.  It overrides the formatting options normally settable by changing case of the PDF file extension.  The value must consist of the letters PDF in one of the valid case combinations.
GCS_NOA4STRIP[CV G>] This variable can be set in FAXFACTS.CFG, or a template passed to GCSINGLE, or set for a COPIAFACTS conversion, of a TIF original to an A4 PDF. A non-empty value suppresses the automatic reduction of completely blank 6mm strips on the left and/or right margins, which by default reduces the amount by which an 1728-pixel, 244mm-wide TIF has to be reduced to fit an A4 page.
GCT_EXPANDnn[CV G>] This variable is created in the FS file when a graphical cover sheet has been processed in the presence of the Keep Graphical Cover CopiaFacts option.  It records the filename which has been 'kept'.  The nn is zero for the fax cover sheet and is incremented for $fax_filename lines referencing a graphical cover sheet.
GSPDFx[CV >V] These variables (for x=1 to x=9) are used to override the Ghostscript command parameters used for Document Conversion using Ghostscript.  Variables with numbers 6 and above must be defined sequentially with no gaps in the number sequence.
GTD_CHECK [SW] For Dialogic and Dialogic Diva boards, this variable is used to set the tone-IDs of the global tones that are to be detected on the voice channel. For example a value of "1 2 4" selects tone IDs 1, 2, and 4 defined by $global_tone for the line. Detection (or change of detected tones) is not actually enabled until the next voice play or record operation on the line. Detection terminates a play or record operation. The addition of a minus sign at the end of the string (e.g. "1 2 4 -") disables detection at the end of the play or record operation. Any assignment to this variable immediately resets the value of GTD_TONEID to zero. The value "all" or "all-" enables all defined tones.
GTD_TONEID [SRO] This variable returns the tone-ID (from 1 to 32) of the last global tone detected on the Dialogic or Dialogic Diva voice line, or 0 if no tone has been detected. If non-zero, the number will be one of those defined in the last assignment to GTD_CHECK.