12 Nov
2012
12 Nov
'12
2:08 p.m.
The NeXT printer, if memory serves, connects to the
desktop machine
via a DE9 connector. This suggests (at least I think it does) that
there's another board in there that's talking to the DC controller...I
don't think nine pins is enough for the whole "dumb" control interface,
especially if there are high-speed differential signals in the mix
eating up a pair of lines.
Agreed. The Canon VDO interfce conenctor (on the CX-VDO and SX-VDO) is a
DC37.Qutie a lot of the pins are grounds (return for single-ended
signals), but there are stil lqutie a few active pins,
FOr 300 dpi, the laser on/of signal can be changing at almost 30MHz IIRC.
Sendign that down a non-differtail log cable is asking for troublew There
is no data buffer memory in these pritners, you have to keep the data
rate up once you start a page.
My guess is that you're right. There is some extra electroncis in the
NeXT pritner. I can thinkl of at least 2 possibilites. One is that the 2
differntial signasl (laser on/off and beam detcat) are send
differentially over 4 of the pins onthe DE9, there's then some kind of
lower speed interfce to hadnle comamnds, status, startign a page, etc on
the remainign pisn. The other possibility is that tere is a data buffer
in thepritner whic his loaded form the host and then sends data to the
laser controller at the full rate.
-tony