Mark Levinson RS-232 Use and maintenance manual

1
No320S preamplifier
RS-232 control guide

2
Overview
Overview The Mark Levinson No320S preamplifier is equipped with an RS-232
control port. A complete set of command inputs and status outputs allow control of
the No320S by an external control system (such as AMX or Crestron). This guide
contains connection details and the RS-232 command list.
Contacting
Technical
Support
Phone
860-346-0896
9am to 5pm EST Monday thru Friday
Fax
860-347-6251
Please allow 24hrs for reply
Email
[e-mail]
Please allow 24hrs for reply

3
Connection
RS-232 Port
Location RS-232 control is through an RJ-11 connector located on the back of the No320S next
to the IR output. This connector has 6 pins of which only three are used for
communication.
RS-232 Port Pin
Configuration. The No320S will receive control data on pin 2 Data Receive and transmit status data
on pin 3 Data Transmit. The connection Cable between the No320S and the control
device will need to be configured so that the No320S’s receive is connected to the
control devices transmit. Please refer to the product owner’s manual for the control
device you are using for RS-232 port type and configuration.
Pin 2 Rx from the PC / Data Receive
Pin 3 Tx to the PC / Data Transmit
Pin 5 Digital system ground
RX TX GND

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RS-232 Control
Cable Madrigal Audio Labs offers several parts to help communicate via RS-232 to the
No320S. The following parts can be order from Madrigal Audio Labs Technical
Support.
Part # Description
MRC878 DSUB9 to RJ-11 Adaptor and 2 meter RJ-11 to RJ-11 Cable
MRC808 DUB9 to RJ-11 Adaptor
MLC732 2 meter RJ-11 to RJ-11 Cable
For general purpose and short cable runs to the No320S, Part # MRC878 contains
everything needed.
For cable lengths of more then 2 meters - Part # MRC808 and the length of cable
needed should be ordered.
RS-232 control units with port types other then DSUB9 will need to have the cable
constructed. To construct a cable please follow the example below.
Control Cable
Example As an example on making the cable we will use the most common connector used,
which is a DSUB9. The No320S only needs 3 pins to control the unit via RS-232. As
mentioned earlier the No320S’s pin 2 Data Receive must connect to the control
devices Transmit. Please read the notes below before constructing the RS-232
cable.
qVerify Control Devices RS-232 Port Type and Configuration – Refer to Control
Device Owners Manual
qDetermine length of cable needed – Check the control device owners manual for
length limitations
qHave all available parts
Before
Constructing the
Communications
Cable
o Length of Cable needed
o RJ-11 Connector
o Connector type used by RS-232 device
Cable Layout The following diagram shows how to construct a basic DSUB9 to RJ-11 Cable.
Cable Connections
No320S RS-11
Pins
Controller DSUB9
Pins
1 – NOT USED NO CONNECTION
2 – Data Receive -----Connect to----- 3 – Data Transmit
3 – Data Transmit -----Connect to----- 2 – Data Receive
4 – NOT USED NO CONNECTION
5 – Digital Ground -----Connect to----- 5 – Digital Ground
6 – NOT USED NO CONNECTION

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Diagram 2 – RJ-11 to DSUB9 Cable
Pa rts Use d fo r C a b le
Digikey Pa rt# Radioshack Part #
(1) - 9 pin DSUB Female Connector A2047-ND 276-1537
(2) - 6 pin RJ-11 Connector A9027-ND 279-421
(3) - 9 pin DSUB Housing A9001-ND 276-1539
(4) - 6 Conductor Data / Phone Cable H0063 (length in feet)-ND 910-2319
(1) - 9 pin DSUB Fema le Inside View
(3) - 9 pin DSUBHousing
A sse m b le
p
e r m a n ufa c ture rs s
p
e c ific a t io ns
(2) - 6 Pin RJ-11 Connector
NO TE O rie nt a t io n o f
wiresand Attach as
sh o w n
Strip Insu la tio n p e r RJ-11
manufac turers
In st ru c t io n s
NO TE O rie nt a t io n o f
RJ-11 w ith C lip Fa c ing
Down
(4) - 6 Conductor Data / Phone Cable
Cut wires
1 / 4 / 6
from cable

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Command list
Settings: 38.4K baud, 1 stop bit, no parity
Format: !<command><cr> or !Vxx.x<cr>
The '!' is used as a framing character and can be sent any time to reset the
packet reception code. Note that all commands are 5 bytes ( '!' + 3char command
+ <cr> ) with the exception of the direct volume command which is 7 bytes ( '!' +
'V' + 4 bytes data + <cr> ) <cr> = 0x0d, carrage return.
Example: !GI1<cr> ( selects input 1 on No320S)
Keys:
COMMAND DESCRIPTION
KVD Volume "key" down
KVU Volume "Key" up
KBA Balance Key
KSU Setup Key
KEN Enter Key
KST Standby Key
KMU Mute Key
KMO Mono Key
KIP Input select previous "key"
KIN Input select next "key"
KPO polarity key
KDI Display Intensity key
Note on ramping volume:
Repeated “EV_VOL_DOWN” or “EV_VOL_UP” key commands must be
sent at less than 150mS intervals to cause a smooth, accelerated ramping of
volume like the effect of holding the volume up or down key on the remote
control.
Directs:
COMMAND DESCRIPTION
GOP Go to Operate mode
GST Go to Standby mode
GMU Go to mute
GMN Restore volume
GI1 Go to input 1

7
GI2 Go to input 2
GI3 Go to input 3
GI4 Go to input 4
GI5 Go to input 5
GI6 Go to input 6
GI7 Go to input 7
Note: “GI7”selects either input 7 or phono input if installed.
GBA Go to balance mode
GBE Exit balance mode
IOF Go to display intensity 0
I25 Go to display intensity 25%
I50 Go to display intensity 50%
IFU Go to display intensity 100%
Status:
COMMAND DESCRIPTION
MON Enable RS232 status updates
(default)
MOF Disable RS232 status updates
Note: The monitor on/off setting is not saved
and restored through power off->on cycles
Volume direct:
COMMAND DESCRIPTION
Vxx.x Set volume level directly
Note: Rounds to nearest whole dB step for volumes less that
23.0
Example: V65.0<cr> (sets No320S volume to 65.5)
Query:
COMMAND DESCRIPTION
QAL Request entire current No320S status
Note: Sends all 6 status lines shown below regardless of
monitor on/off

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Status Update:
Any change in the following 6 control keys will automatically send out the
corresponding ASCII string.
CONTROL KEY RETURNED VALUE COMMENT
Select knob 1:IN:<1-7>:<input alias><cr> or
1:IN:NONE<cr> if no current valid input
selection input alias> is max 7 chars, no
null termination
input alias = first 7 ascii
characters from No320S
LED display.
Volume knob 2:VOL:xx.x<cr> or 2:VOL:OFF<cr> xx.x = last 4 ascii characters
from No320S display
Mute 3:MUTE:ON<cr> or 3:MUTE:OFF<cr> ON = user mute engaged,
OFF = normal volume
Mono 4:MONO:ON<cr> or 4:MONO:OFF<cr> ON = mono , OFF = normal
stereo
Polarity 5:POL:ON<cr> or 5:POL:OFF<cr> ON = polarity reversed, OFF
= normal
Standby 6:STDBY:ON<cr> or 6:STDBY:OFF<cr> ON = standby active, OFF =
normal operating mode