[rescue]   Trying to get Cadmus 9200 running (serial console trouble)

Meelis Roos mroos at linux.ee
Wed Feb 6 01:29:50 CST 2019

> On reading this blog
> http://www.pcs-cadmus.de/en/blog/2016/05/06/cadmus-and-pdp11/
> The systems are essentially the old Dec LSI Qbus systems with the LSI proc
> replaced with a Motorola one. Importantly it states that the serial console is
> based on the DLV11-J board, is that the case here?

Serial board DLV11-J seems to be a dual QBUS card. Something similar is described
in Cadmus manual as SLU-4 but SLU-4 drawing looks slightly different than the
images of DLV11-J (but both are dual QBUS). The manual tells that drivers for
SLU-4 also work for DLV11-F and DLV11-B that can also be used in Cadmus 9200 systems.
Another place notes that SLU-4 is fully compatible with DLV11-J from DEC and with
GTSC 304 from Grant Technology Systems.

The card that my 9230 has is MUX-KE2. That is a quad QBUS card with 2 40-pin
connectors of 4 ports each  plus a third 40-pin connector for MUX-EXT that can
supply 8 more ports with handshake lines. MUX-KE2 uses AM29xx controllers and use DMA.
MUX-KE2 first 4 ports have hardware flow control and next 4 ports only Tx-Rx-GND
(at least by the docs - internal ribbon cables to all the ports seem to have 8 wires).
The first 4 ports have signals GND TxC TxD RxC RxD RTS CTS DTR DCD and "TxC ext"
(external or internal clock seems to be settable via jumpering).

Found another mention of the serial cards. Rough translation: SLU-4 together with
MUX-KE emulates a DH11 board. Up to 4 SLU4's can be attached to one MUX-KE. So MUX-KE
and MUX-KE2 seem to be different.

I took a voltmeter and measured the pins on console port. I am not sure which way to
number the pins, but pins 2 4 and 7 or 8 have -12V voltage compared to the rest.
2 and 4 seem to be TxD and RTS, 7 is DTR and 8 DCD - so probably RTS, DTR and TxD
are set to something (why -12V instead of +12?).

I really should scan and share at least the hardware manual (in German but readable
even for someone like me with weak German skills). But it will take time.

The manual tells explicitly that terminal should have 9600 8N1.

I will measure the cable and check parity settings too.

Meelis Roos <mroos at linux.ee>

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