Heading:
Lavender Box
Page Numbers: Yes X: 527 Y: 10.5"
Inter-Office Memorandum
ToAudio InterestDateJanuary 23, 1980
FromL. StewartLocationPalo Alto
SubjectAn interface facility forOrganizationCSL
the Auburn Audio Board
XEROX
Filed on: <LStewart>Audio>Lavender.bravo
Introduction
We envision three stages of external interface hardware for Auburn. The first and simplest consists of a 4-wire telephone set (e.g Danray) connected via cable to Auburn. The intermediate device, which is the subject of this note, is called Lavender. Lavender contains no active components; it supports a collection of connectors for easy attachment of a variety of audio devices to Auburn. The third device, called Violet, is more complex and includes some active components. We envision the Violet Box as containing a hybrid and some audio switching suitable for the support of a variety of telephone like devices as well as connectors.
This note describes Lavender. The box is larger than it needs to be and there are extra connectors specified that will allow a Lavender box to be upgraded to a Violet box. The intent is that the conversion from Lavender to Violet be possible without drilling any new holes.
These specifications should not be considered absolute. We are open for suggestions!
Lavender
The Lavender Box is a weighted box 8"x8"x3" containing no active components. A 25 wire cable runs to the Alto rear connector panel and a variety of connectors are mounted on the box.
The size 8" square and 3" high is only a suggestion. Perhaps it should be metric.
The box should be reasonably heavy to make it easier to plug and unplug the various connectors. The cables coming out the back should not pull the box off a table.
Two DB-25S connectors for cables to the Alto. One of these is for Violet expansion purposes.
A 15 pin connector for a Danray telephone (DA15-S).
A pair of 5-way binding posts for connecting a speaker. (There is also an L-pad speaker volume control and a switch to turn off the speaker.)
A pair of headphone jacks (1/4" stereo phone jacks).
A microphone jack (1/4" mono phone jack).
A collection of connectors for preamp (line) level signals, both input and output (RCA phono jacks). A couple of these are currently unused; they are for Violet expansion.
An additional hole plus cover plate on the rear panal. Since we are currently uncertain about the required connectors for Violet, it seems best to keep our options open. There is also a rear panal hole with temporary snap-in cover that could be used for a power cord.
Some mounting holes for an internal circuit board for Violet.
Box surface finish and labeling - to be determined.
Alto Internal Cables
The Auburn Audio board connects to the world through two 26-wire ribbon cables. This section details the construction of the Auburn Internal Cables, which connect the board to the Alto rear connector panel. There are two identical cables, the Auburn Analog cable and the Auburn Digital cable. Each cable consists of an appropriate length of 26 wire ribbon cable (0.050 inch spacing). The Auburn end of the cable is attached to a 3M 3399-3000 connector (or equivalent). The connector panel end is attached to a DB-25S connector. Notice that wire number 8 (The fifteenth wire from the red edge of the cable) is omitted from the DB connector.
Analog Cable
Wire #DB-25 pinSignal
1 1NC
1414NC
2 2+V
1515Gnd
3 3 -
1616Gnd
4 4AmpOut
1717Gnd
5 5 -
1818Gnd
6 6MicIn
1919Gnd
7 7PreAmpIn
2020Gnd
8unused
21 8Gnd
921PreAmpA
22 9Gnd
1022PreAmpB
2310Gnd
1123TelOut
2411Gnd
1224TelIn
2512Gnd
1325-V
2613Gnd
Digital Cable
Wire #DB-25 pinSignal
1 1+5V
1414Output
2 2Input LSB
1515Output
3 3Input Bit x
1616Output
4 4Input Bit x
1717Output
5 5Input Bit x
1818Output
6 6Input Bit x
1919Output
7 7Input Bit x
2020Output
8unused(Input Bit x)
21 8Output
921Input Bit x
22 9Output
1022Buff Out OH
2310Output
1123Buff Out
2411Output
1224Buff Out
2512OKToPhone
1325Buff Out
2613Gnd
Danray Only Cable
Note: This section does not apply to Lavender.
The simplest connection to Auburn consists of a 4-wire telephone set such as a Danray Set. The cable between Danray and Auburn consists of three twisted pairs between a DB-25P (Alto end) and a DA-15S (Danray end). A slight complication is the required installatiuon of a DC blocking capacitor inside the DA-15S connector housing. In the table below, the twisted pairs are shown by the separation into three groups of two wires.
DB-25PDA-15SSignal
2 2+12V
15 3Ground
23 6TelOut
11 7Ground
24 4TelIn (via 0.01 mf 100V cap.)
12 5Ground
Danray only cable:
Belden 9745, 3 twisted pairs #22 standed cable or eqv.
3M #3399-3000 socket connectors (2) or eqv.
DB-25P connector (1).
DA-15S connector (1).
0.01 microfarad 100 volt capacitor (for mounting inside DA-15S).
Alto to Lavender cable
The cable from the Alto rear connector panel to the Lavender box is a pin to pin 25 wire cable between two DB-25P connectors.
Lavender Internal
See the attached drawings for internal details about the Lavender box and its mechanical layout.
Lavender Parts
These components are intended only as a guide. All suggested part numbers and manufacturers should be considered "or equivalent".
Internal Cables:
3M Scotchflex 3365/26 ribbon cable.
3M #3399-3000 socket connectors (2).
3M #3483-1000 (DB-25S) connectors (2).
Alto to Lavender cable:
3M Scotchflex 3365/26 ribbon cable.
3M #3482-1000 (DB-25P) connectors (2).
Lavender box:
DB-25S connector (1).
DA-15S connector (1).
0.01 microfarad 100v capacitor.
82 ohm 1 watt resistors (2).
8 ohm 2 watt resistor (1).
2.2K ohm 1/2 watt resistors (2).
Phono jacks (RCA style) (8) (Switchcraft #3501FP).
1/4" mono phone jack for microphone input (1) (Switchcraft #11).
1/4" stereo phone jack for headphones (2) (Switchcraft #12B).
SPDT minature toggle switch (1) (ALCO).
8 ohm L-pad for speaker volume (1) ( ).
5-way binding posts for speaker. (H. H. Smith #269BB).