	README	4.5	(2.11BSD) 2020/3/24

Brief description of the tab format. It is essentially the same as 
ditroff has, but has no required order of the entries.
Also # in the first column is a comment.

First 23 entries are description of printer functionality.

There are 240 units per inch.
In order; first nine are integers.

bset            Bits to be set for printing (in stty sg_flags)
breset          Bits to be cleared for printing (in stty sg_flags)
Hor             # of units for horiz. motion
Vert            # of units for vertical. motion
Newline         # of units for newline
Char            # of units wide a character is
Em              # of units an 'em' is.
Halfline        # of units a halfline vertical motion is.
Adj             # of units for horizontal motion

Following are strings (or empty strings).
twinit          Init string (for terminal)
twrest          Restore string (for terminal)
twnl            Newline character sequence
hlr             Half-line reverse
hlf             Half-line forward
flr             Full-line reverse
bdon            Turn on bold
bdoff           Turn off bold
ploton          Start plot mode
plotoff         Stop plot mode
up              Up (in plot mode)
down            Down (in plot mode)
right           Right (in plot mode)
left            Left (in plot mode)

Thereafter are special characters or moves. Only the defined ones
need to be present.

Format; example of a square.
char	size	string
sq	2	[]

The string is encoded like:
        bit 7:  set: Plot mode
                bit 5-6: right/left/down/up
                bit 0-4: # of times
        bit 7:  clear: 6-0: character

For control codes C string codes can be used, both octal escapes
as well as normal escapes, like o\b| or \033A.

Here are the currently supported types of printers:

37		Model 37 TeleType
300		old DTC 300, 10 pitch
300-12		old DTC 300, 12 pitch
302		DTC 302 or DTC 300s, 10 pitch (link to 300s and dtc)
302-12		DTC 302 or DTC 300s, 12 pitch (link to 300s-12 and dtc12)
382		fancy DTC 382, 10 pitch
382-12		fancy DTC 382, 12 pitch
450		DASI 450 or IPSI 1622, 10 pitch (link to ipsi)
450-12		DASI 450 or IPSI 1622, 12 pitch (link to ipsi12)
833		AJ 833 or AJ 832, 10 pitch
833-12		AJ 833 or AJ 832, 12 pitch
epson		Epson FX80
itoh		C:ITOH Prowriter, 10 pitch
itoh12		C:ITOH Prowriter, 12 pitch
lpr (default)	printer with no halfline/upline, 10 pitch
			(link to crt and tn300)
nec		NEC 55?0 or NEC 77?0 Spinwriter, 10 pitch,
			Courier-72/Manifold thimble
nec-t		NEC 55?0/77?0 Spinwriter, 12 pitch,
			Tech-Math/Times-Roman thimble
nec12		NEC 55?0 or NEC 77?0 Spinwriter, 12 pitch,
			Courier - 72/Manifold thimble
nec25-t		NEC 5525/7725 Spinwriter, 12 pitch,
			Tech-Math/Times-Roman thimble
qume		Qume Sprint 5 or 9, 10 pitch
qume12		Qume Sprint 5 or 9, 12 pitch
x-ecs		Xerox/Diablo 1730/630, Extended Character Set, 10 pitch
x-ecs12		Xerox/Diablo 1730/630, Extended Character Set, 12 pitch
xerox		Xerox 17?0 or Diablo 16?0, 10 pitch
xerox12		Xerox 17?0 or Diablo 16?0, 12 pitch
