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7000 Series plug-in interface (view source)

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|-
|-
!width="10%"| 
!width="10%"| 
!width="45%"| A side
!colspan="2"| A side
!width="45%"| B side
!colspan="2"| B side
|-
|-
! Pin  
! Pin  
! Function
! colspan="2" | Function
! Function
! colspan="2" | Function
|-  
|-  
|  1 || Sweep Gate (H)  || Delay mode ctl in (H-B)
|  1  
| colspan="2" | Sweep Gate (H)   
| colspan="2" | Delay mode ctl in (H-B)
|-  
|-  
|  2 || Gate common  || Delay mode ctl out (H-A)
|  2  
| colspan="2" | Gate common   
| colspan="2" | Delay mode ctl out (H-A)
|-  
|-  
|  3 || A Sweep (V & H-A) ''[note 1]''    || B Sweep (V & H-B) ''[note 1]''
|  3  
| colspan="2" | A Sweep (V & H-A) ''[note 1]''     
| colspan="2" | B Sweep (V & H-B) ''[note 1]''
|-  
|-  
|  4 || Line trigger || Trigger holdoff (H)
|  4  
| colspan="2" | Line trigger  
| colspan="2" | Trigger holdoff (H)
|-
|-
|  5 || Chop drive  || Aux Swp gate (H)
|  5  
| colspan="2" | Chop drive   
| colspan="2" | Aux Swp gate (H)
|-
|-
|  6 || Chop common  || ALT drive
|  6  
| colspan="2" | Chop common   
| colspan="2" | ALT drive
|-
|-
|  7 || Intensity Limit (H) || MF Channel Switch
|  7  
| colspan="2" | Intensity Limit (H)  
| colspan="2" | MF Channel Switch
|-
|-
|  8 || bgcolor="Pink"| +5 V  ||  Sweep inhibit (H)
|  8  
| colspan="2" bgcolor="Pink" | +5 V   
| colspan="2" |  Sweep inhibit (H)
|-
|-
|  9 || bgcolor="Pink"| +5 V (lights)  || Delay gate (H)
|  9  
| colspan="2" bgcolor="Pink" | +5 V (lights)   
| colspan="2" | Delay gate (H)
|-
|-
| 10 || Single sweep ready (H)  ||  X comp inhibit (H)
| 10  
| colspan="2" | Single sweep ready (H)   
| colspan="2" |  X comp inhibit (H)
|- bgcolor="Yellow"  
|- bgcolor="Yellow"  
| 11 || +Signal || −Signal
| 11  
| colspan="2" | +Signal  
| colspan="2" | −Signal
|- bgcolor="Pink"  
|- bgcolor="Pink"  
| 12 || Signal Ground || Signal Ground  
| 12  
| colspan="2" | Signal Ground  
| colspan="2" | Signal Ground  
|- bgcolor="Yellow"  
|- bgcolor="Yellow"  
| 13 || +Trigger (V) ''[note 2]'' ||  −Trigger (V) ''[note 2]''
| 13  
| colspan="2" | +Trigger (V) ''[note 2]''  
| colspan="2" |  −Trigger (V) ''[note 2]''
|-
|-
| 14 || bgcolor="Pink"| Lights common || Dual beam Aux Y-Axis  
| 14  
| colspan="2" bgcolor="Pink" | Lights common  
| colspan="2" | Dual beam Aux Y-Axis  
|-
|-
| 15 || Single sweep logic || Single sweep reset (H)
| 15  
| colspan="2" | Single sweep logic  
| colspan="2" | Single sweep reset (H)
|-
|-
| 16 || MF Mode  || Aux Y axis  (H)
| 16  
| colspan="2" | MF Mode   
| colspan="2" | Aux Y axis  (H)
|-
|-
| 17 || Aux Z axis  || Aux Z common  
| 17  
| colspan="2" | Aux Z axis   
| colspan="2" | Aux Z common  
|- bgcolor="Pink"
|- bgcolor="Pink"
| 18 || +15 V  || −15 V
| 18  
| colspan="2" | +15 V   
| colspan="2" | −15 V
|- bgcolor="Pink"
|- bgcolor="Pink"
| 19 || +50 V  || −50 V  
| 19  
| colspan="2" | +50 V   
| colspan="2" | −50 V  
|- bgcolor="Yellow"  
|- bgcolor="Yellow"  
| 20 || +Trigger in (H) || −Trigger in (H)
| 20  
| colspan="2" | +Trigger in (H)  
| colspan="2" | −Trigger in (H)
|- bgcolor="Yellow"  
|- bgcolor="Yellow"  
| 21 || +Aux trigger in (H) ''[note 5]''|| −Aux trigger in (H) ''[note 5]''
| 21  
| colspan="2" | +Aux trigger in (H) ''[note 5]''
| colspan="2" | −Aux trigger in (H) ''[note 5]''
|- bgcolor="LightBlue"  
|- bgcolor="LightBlue"  
| 22 || /EOI ''[note 6]'' || /SRQ ''[note 7]''
| 22  
| colspan="2" | /EOI ''[note 6]''  
| colspan="2" | /SRQ ''[note 7]''
|- bgcolor="LightBlue"  
|- bgcolor="LightBlue"  
| 23 || /DAV  || REN  
| 23  
| colspan="2" | /DAV   
| colspan="2" | REN  
|- bgcolor="LightBlue"  
|- bgcolor="LightBlue"  
| 24 || /IFC  ''[note 3]'' || /ATN
| 24  
| colspan="2" | /IFC  ''[note 3]''  
| colspan="2" | /ATN
|- bgcolor="LightBlue"  
|- bgcolor="LightBlue"  
| 25 || /NDAC || /NRFD
| 25  
| colspan="2" | /NDAC  
| colspan="2" | /NRFD
|- bgcolor="LightBlue"
|- bgcolor="LightBlue"
| 26 || Logic Common || /SND <br />or Inter-plugin GND ''[note 8]''
| 26  
|- bgcolor="Pink"
| colspan="2" | Logic Common  
| 27 || −5.2 V ''[note 4]'' <br />or Inter-plugin link || 5.1 V ''[note 4]'' <br />or Inter-plugin link
| colspan="2" | /SND <br />or Inter-plugin GND ''[note 8]''
|-  
| 27
| bgcolor="Pink" | −5.2 V<br />''[note 4]''  
| Inter-plugin<br />link  
| bgcolor="Pink" | +5.1 V<br />''[note 4]''  
| Inter-plugin<br />link  
|-
|-
| 28 || Inter-plugin link || Inter-plugin link
| 28  
| colspan="2" | Inter-plugin link  
| colspan="2" | Inter-plugin link
|- bgcolor="LightGreen"
|- bgcolor="LightGreen"
| 29 || TS10  ''[note 3]'' || TS9 ''(DIO8)''
| 29  
|- bgcolor="LightGreen"
| colspan="2" | TS10  ''[note 3]''  
| 30 || TS8 ''(DIO7)''  || TS7 ''(DIO6)''
| bgcolor="LightGreen" | TS9  
|- bgcolor="LightGreen"
| bgcolor="LightBlue"  | ''DIO8''
| 31 || TS6 ''(DIO5)''  || TS5 ''(DIO4)''
|-  
|- bgcolor="LightGreen"
| 30
| 32 || TS4 ''(DIO3)''  || TS3 ''(DIO2)''
| bgcolor="LightGreen" | TS8
|- bgcolor="LightGreen"
| bgcolor="LightBlue"  | ''DIO7''   
| 33 || TS2 ''(DIO1)''  || TS1 ''[note 3]''
| bgcolor="LightGreen" | TS7
| bgcolor="LightBlue"  | ''DIO6''
|-  
| 31
| bgcolor="LightGreen" | TS6
| bgcolor="LightBlue"  | ''DIO5''   
| bgcolor="LightGreen" | TS5
| bgcolor="LightBlue"  | ''DIO4''
|-  
| 32
| bgcolor="LightGreen" | TS4
| bgcolor="LightBlue"  | ''DIO3''   
| bgcolor="LightGreen" | TS3
| bgcolor="LightBlue"  | ''DIO2''
|-  
| 33
| bgcolor="LightGreen" | TS2
| bgcolor="LightBlue"  | ''DIO1''   
| colspan="2" bgcolor="LightGreen" | TS1 ''[note 3]''
|-
|-
| 34 || n.c.  || n.c.  
| 34  
| colspan="2" | n.c.   
| colspan="2" | n.c.  
|-  
|-  
| 35 || bgcolor="LightGreen"| Force readout || Plugin mode ''[note 8]''
| 35  
| colspan="2" bgcolor="LightGreen" | Force readout  
| colspan="2" | Plugin mode ''[note 8]''
|-
|-
| 36 || n.c. || n.c.  
| 36  
| colspan="2" | n.c.  
| colspan="2" | n.c.  
|- bgcolor="LightGreen"
|- bgcolor="LightGreen"
| 37 || Ch. 1 Col  || Ch. 1 Row  
| 37  
| colspan="2" | Ch. 1 Col   
| colspan="2" | Ch. 1 Row  
|- bgcolor="LightGreen"
|- bgcolor="LightGreen"
| 38 || Ch. 2 Col  || Ch. 2 Row  
| 38  
| colspan="2" | Ch. 2 Col   
| colspan="2" | Ch. 2 Row  
|-
|-
|}
|}


===Pin group function legend===
===Pin group function legend===
:{| cellpadding="4"
{| cellpadding="4"
|-
|-
| bgcolor="Pink" | Plugin power
| bgcolor="Pink" | Plugin power
Line 111: Line 197:
| bgcolor="LightGreen" | [[7000 series readout system|Readout system]] signals
| bgcolor="LightGreen" | [[7000 series readout system|Readout system]] signals
|-
|-
| bgcolor="LightBlue"  | IEEE-488 bus used in [[7A16P]], [[7A29P]], [[7B90P]], digitizer mainframes; data 1-8 on TS2-TS9 lines
| bgcolor="LightBlue"  | IEEE-488 bus<br /> (used in [[7A16P]], [[7A29P]], [[7B90P]], digitizer mainframes) 
|}
|
===Description of signals===
* ''Sweep Gate'' − 0/+5 V, high while sweep is running (beam unblanking), connected to +5 V in amplifier plugins; +Gate Output on mainframe uses Sweep Gate from H slot A when A Gate is selected, and from H slot B when B is selected.
* ''Delay Mode Control'' − Output on delaying timebase in horizontal slot A, connected to input on delayed timebase in horizontal slot B.  >+3 V disables auto sweep in delayed timebase; 0 V enables independent timebase function.  Grounded in amplifier plugins.
* ''A/B Sweep'' − 500 mV<sub>p-p</sub>, negative-going copy of sweep signal from timebase, not affected by X position control or magnifier; Used for mainframe's Sawtooth Out, additionally fed to V plugins.
* ''Line Trigger'' − Approx. 3 V<sub>RMS</sub> mains-frequency signal from power supply (through transformer).
* ''Trigger Holdoff'' − 0/+5 V, generated by time-base, high during holdoff time of time-base, used in mainframe for ALT sequencing.
* ''Chop Drive'' − 0/+5 V; switches at one-half the rate of the VERTICAL MODE CHOP signal; high level selects channel 2, low level selects channel 1 of a dual-trace plug-in.
* ''Aux Sweep Gate'' − 0/+5 V; pulled high by dual-sweep time-base plug-ins during auxiliary sweep.
* ''Alt Drive'' − 0/+5 V; high level will display channel 2 of a dual-trace plug-in, low will display channel 1.
* ''Intensity Limit'' − Switched to ground by timebase in slow sweep speeds (≥100 ms/Div), limits beam intensity to protect the CRT [[phosphor]].
* ''Mainframe Channel Switch'' − -0.6/+1.1 V logic levels; plug-in output is displayed when MF Channel Switch ≠ MF Mode (XOR).
* ''Mainframe Mode'' − 0/+5 V logic levels; plug-in output is displayed when MF Channel Switch ≠ MF Mode (XOR).
* ''Sweep Inhibit/Sweep Lockout'' - Mainframe injects current > 1 mA to prevent time base from sweeping. Used for ALT sequencing and delayed sweep of the ''B'' time base.
* ''Delay Gate'' − negative-going pulse starting at the end of the delay period, and lasting until the end of the sweep from the delaying timebase. Mainframes connect this signal from the ''A'' timebase through a 2 k resistor and a diode to B8 ''Sweep inhibit'' of the ''B'' time base to trigger the delayed sweep. +Gate Output on mainframe uses Delay Gate from H slot B when Delay Gate is selected.  Grounded in amplifier plugins.
* ''Single sweep ready'' − 0/+5 V, high when single sweep is ready.
* ''X comp. inhibit'' − Connected to ground in amplifiers, switched to ground by timebase set to amplifier (X-Y) mode to enable X-Y delay compensation in scopes with that function ([[7904|7904 Opt.2]], [[7104|7104 Opt.2]]).
* ''Signal'' − Signal output from plugin to mainframe.  Differential, 50 Ω per side. 50 mV/Div (differential).
* ''Trigger'' − Copy of signal output from V plugin to mainframe.  Differential, 50 Ω per side. 50 mV/Div (differential). Terminated on H slots.
* ''Dual Beam Aux Y-Axis'' − Used in dual beam mainframes ([[7844]]), Current-driven input to mainframe allowing vertical separation of two traces with dual timebase plugins. 1 mA/Div sensitivity.
* ''Single Sweep Logic'' − 0/+5 V; high level when time-base is in single sweep mode.
* ''Single Sweep Reset'' − Switched to ground to reset single sweep.
* ''Aux Y Axis'' − Current-driven input to mainframe allowing vertical separation of two traces with dual timebase plugins. 1 mA/Div sensitivity; driven only when plug-in output is displayed (see ''MF Ch Switch'' above).
* ''Aux Z Axis'' − Current-driven input to mainframe allowing plugins to modulate beam intensity, e.g. in dual timebase A intensified by B display mode; driven only when plug-in output is displayed (see ''MF Ch Switch'' above).
* ''Trigger In'' − Trigger signal input on H plugin, routed from V plugin's trigger output.  Differential, 50 Ω per side, 50 mV/Div (differential).
* ''Aux Trigger In'' − Provided by 1<sup>st</sup> generation 7000 series mainframes ([[7704]], [[7504]], [[7503]], [[7403N]]).  Only known use is in the [[7B52]] timebase as an optional source for the delayed trigger.  Four-bay mainframes supply the trigger signal from the left horizontal bay to Aux Trig In on the right horizontal bay and vice versa, via 510 Ω resistors.  Three-bay mainframes supply the Left Vert trigger signal via 510 Ω resistors.
* ''Inter-Plugin Connections'' − In 1<sup>st</sup> generation 7000 series mainframes ([[7704]], [[7504]], [[7503]], [[7403N]]), pins 26B, 27A/B and 28A/B are inter-plugin connections.  In the 3-bay mainframes, right vertical slot pins 27A, 27B, 28A, 28B are connected via 50 Ω striplines to horizontal slot pins 27B, 27A, 28B, 28A respectively, with ground on 26B.  Four-slot mainframes additionally make the same connections from the left vertical slot to the right horizontal slot.  ''More information needed - were any plug-ins made that used these?''
* ''GPIB lines'' − Control signal functions are the same as their [[GPIB interface|IEEE-488 (GPIB)]] equivalents.  Time slot lines 2 to 9 double as IEEE-488 data lines.
* ''TS1−TS10'' − [[7000 series readout system|readout system]] time slot pulses.  Idle 0, active −15 V.
* ''Force Readout'' − Allows plug-in readout information to be displayed regardless of the mainframe mode switch setting when pulled low (<0.5 V). Used by several 7DXX plug-ins.
* ''Plugin Mode'' − 5-level signal providing the mainframe with information about the operating mode of a dual-trace or dual-sweep plugin.
* ''Ch1/2 Row/Col'' − Analog current inputs to the readout system. Ch1 refers to the first channel within the plugin slot in question and is associated with the readout field on top of the screen. Ch2 is the 2nd channel displayed at the bottom.  Row/Current signals accept negative currents in 100 μA steps; typically, plugins contain resistors from time slot signal lines to row/current lines.
|}
|}


===Power Supply Load Limits===
===Power Supply Load Limits===
According to the [[7A17]] manual, the total allowed DC power consumption for each plugin is 16.5 W. The individual current limits are shown below.
According to the [[7A17]] manual, the total allowed DC power consumption for each plugin is 16.5 W, with individual current limits as shown below.


:{| class="wikitable"
:{| class="wikitable"
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|-
|-
| Chop || 0-47 Ω || 0 V
| Chop || 0-47 Ω || 0 V
|}
[[Image:7000 slot pinout.jpg|thumb|400px|left]]
|
===Description of signals===
* ''Sweep Gate'' − 0/+5 V, high while sweep is running (beam unblanking), connected to +5 V in amplifier plugins; +Gate Output on mainframe uses Sweep Gate from H slot A when A Gate is selected, and from H slot B when B is selected.
* ''Delay Mode Control'' − Output on delaying timebase in horizontal slot A, connected to input on delayed timebase in horizontal slot B.  >+3 V disables auto sweep in delayed timebase; 0 V enables independent timebase function.  Grounded in amplifier plugins.
* ''A/B Sweep'' − 500 mV<sub>p-p</sub>, negative-going copy of sweep signal from timebase, not affected by X position control or magnifier; Used for mainframe's Sawtooth Out, additionally fed to V plugins.
* ''Line Trigger'' − Approx. 3 V<sub>RMS</sub> mains-frequency signal from power supply (through transformer). ''Present on all slots.''
* ''Trigger Holdoff'' − 0/+5 V, generated by time-base, high during holdoff time of time-base, used in mainframe for ALT sequencing.
* ''Chop Drive'' − 0/+5 V; switches at one-half the rate of the VERTICAL MODE CHOP signal; high level selects channel 2, low level selects channel 1 of a dual-trace plug-in.
* ''Aux Sweep Gate'' − 0/+5 V; pulled high by dual-sweep time-base plug-ins during auxiliary sweep. Used to deliver the realtime clock signal from [[7B87]] to [[7854]].
* ''Alt Drive'' − 0/+5 V; high level will display channel 2 of a dual-trace plug-in, low will display channel 1.
* ''Intensity Limit'' − Switched to ground by timebase in slow sweep speeds (≥100 ms/Div), limits beam intensity to protect the CRT [[phosphor]].
* ''Mainframe Channel Switch'' − −0.6/+1.1 V logic levels; plug-in output is displayed when MF Channel Switch ≠ MF Mode (XOR).
* ''Mainframe Mode'' − 0/+5 V logic levels; plug-in output is displayed when MF Channel Switch ≠ MF Mode (XOR).
* ''Sweep Inhibit/Sweep Lockout'' - Mainframe injects current > 1 mA to prevent time base from sweeping. Used for ALT sequencing and delayed sweep of the ''B'' time base.
* ''Delay Gate'' − negative-going pulse starting at the end of the delay period, and lasting until the end of the sweep from the delaying timebase. Mainframes connect this signal from the ''A'' timebase through a 2 k resistor and a diode to B8 ''Sweep inhibit'' of the ''B'' time base to trigger the delayed sweep. +Gate Output on mainframe uses Delay Gate from H slot B when Delay Gate is selected.  Grounded in amplifier plugins.
* ''Single sweep ready'' − 0/+5 V, high when single sweep is ready.
* ''X comp. inhibit'' − Connected to ground in amplifiers, switched to ground by timebase set to amplifier (X-Y) mode to enable X-Y delay compensation in scopes with that function ([[7503]], [[7504|7504 Opt.02]], [[7704|7704 Opt.02]], [[7904|7904 Opt.02]], [[7104|7104 Opt.02]]).
* ''Signal'' − Signal output from plugin to mainframe.  Differential, 50 Ω per side. 50 mV/Div (differential).
* ''Trigger'' − Copy of signal output from V plugin to mainframe.  Differential, 50 Ω per side. 50 mV/Div (differential). Terminated on H slots.
* ''Dual Beam Aux Y-Axis'' − Used in dual beam mainframes ([[7844]]), Current-driven input to mainframe allowing vertical separation of two traces with dual timebase plugins. 1 mA/Div sensitivity.
* ''Single Sweep Logic'' − 0/+5 V; high level when time-base is in single sweep mode.
* ''Single Sweep Reset'' − Switched to ground to reset single sweep.
* ''Aux Y Axis'' − Current-driven input to mainframe allowing vertical separation of two traces with dual timebase plugins. 1 mA/Div sensitivity; driven only when plug-in output is displayed (see ''MF Ch Switch'' above).  Not available in early mainframes e.g. [[7504]], [[7704]] non-A.
* ''Aux Z Axis'' − Current-driven input to mainframe allowing plugins to modulate beam intensity, e.g. in dual timebase A intensified by B display mode; driven only when plug-in output is displayed (see ''MF Ch Switch'' above).
* ''Trigger In'' − Trigger signal input on H plugin, routed from V plugin's trigger output.  Differential, 50 Ω per side, 50 mV/Div (differential).
* ''Aux Trigger In'' − Provided by 1<sup>st</sup> generation 7000 series mainframes ([[7704]], [[7504]], [[7503]], [[7403N]]).  Only known use is in the [[7B52]] timebase as an optional source for the delayed trigger.  Four-bay mainframes supply the trigger signal from the left horizontal bay to Aux Trig In on the right horizontal bay and vice versa, via 510 Ω resistors.  Three-bay mainframes supply the Left Vert trigger signal via 510 Ω resistors.
* ''Inter-Plugin Connections'' − In 1<sup>st</sup> generation 7000 series mainframes ([[7704]], [[7504]], [[7503]], [[7403N]]), pins 26B, 27A/B and 28A/B are inter-plugin connections.  In the 3-bay mainframes, right vertical slot pins 27A, 27B, 28A, 28B are connected via 50 Ω striplines to horizontal slot pins 27B, 27A, 28B, 28A respectively, with ground on 26B.  Four-slot mainframes additionally make the same connections from the left vertical slot to the right horizontal slot.  ''More information needed - were any plug-ins made that used these?''
* ''GPIB lines'' − Control signal functions are the same as their [[GPIB interface|IEEE-488 (GPIB)]] equivalents.  Time slot lines 2 to 9 double as IEEE-488 data lines.
* ''TS1−TS10'' − [[7000 series readout system|readout system]] time slot pulses.  Idle 0, active −15 V.
* ''Force Readout'' − Allows plug-in readout information to be displayed regardless of the mainframe mode switch setting when pulled low (<0.5 V). Used by several 7DXX plug-ins.
* ''Plugin Mode'' − 5-level signal providing the mainframe with information about the operating mode of a dual-trace or dual-sweep plugin.
* ''Ch1/2 Row/Col'' − Analog current inputs to the readout system. Ch1 refers to the first channel within the plugin slot in question and is associated with the readout field on top of the screen. Ch2 is the 2nd channel displayed at the bottom.  Row/Current signals accept negative currents in 100 μA steps; typically, plugins contain resistors from time slot signal lines to row/current lines.
|}
|}


==Links==
==Links==
 
* [[Repairing 7000-series plug-in sockets]]
* [[Media:Tek 7000-series plug-in mainframe interface manual ocr.pdf|Tektronix 7000-Series Plug-in to Mainframe Interface Manual (PDF)]]
* [[Media:Tek 7000-series plug-in mainframe interface manual ocr.pdf|Tektronix 7000-Series Plug-in to Mainframe Interface Manual (PDF)]]
* [[Media:Introduction to the 7000 Series Switching and Logic Circuits (Ken Parker, 1970).pdf| Introduction to the 7000 Series Switching and Logic Circuits (Ken Parker, 1970)]] (PDF,OCR,1MB)
* [[Media:Introduction to the 7000 Series Switching and Logic Circuits (Ken Parker, 1970).pdf| Introduction to the 7000 Series Switching and Logic Circuits (Ken Parker, 1970)]] (PDF,OCR,1MB)
* [https://archive.org/details/tektronix_7000_backplane_Pin_Out Kahrs, ''Interfacing to the Tektronix 7000 series'']
* [https://archive.org/details/tektronix_7000_backplane_Pin_Out Kahrs, ''Interfacing to the Tektronix 7000 series'']
* [[067-0589-00|067-0589-00 rigid extender]]
* [[067-0616-00|067-0616-00 flexible extender]]
* [https://www.ecosensory.com/tek/tek_7K_flex_sales_blurb.txt John Griessen's flex extender kit] / [https://www.ecosensory.com/tek/TEK_7K_FLEX_assy-013-sm.jpg Photo]
==Prototype==
After it was decided that there would be a "New Generation" series of lab scopes to replace the [[500-series scopes|500 series]], concept prototypes were built.
Before [[Howard Vollum]] decided on the height of the New Generation plug-ins, a taller form factor was being considered. This is what it looked like:
<gallery>
Tek 7k concept plug-in pre-prototype 1.jpg|Very Early New Generation Plug-in Prototype
Tek 7k concept plug-in pre-prototype 2.jpg|Very Early New Generation Plug-in Prototype
Tek 7k concept plug-in pre-prototype 3.jpg|Very Early New Generation Plug-in Prototype
Tek 7k concept plug-in pre-prototype 4.jpg|Very Early New Generation Plug-in Prototype
</gallery>
From [[Media:On-The-History-And-Environment-Of-Tektronix.pdf|On the History and Environment of Tektronix]] page 58:
<blockquote>
But [[Howard Vollum|Howard]] then threw another challenge to his group: plug-in height.
Work up through late 1966 had assumed a seven inch plug-in height which would provide room for the needed components using readily available and proven parts.
But the H-P scopes were smaller in size and quite attractive in appearance.
So, one day, Howard said, "the plug-ins will be 5 1/2 inches in height."


[[Oliver Dalton]] recalls the decision to reduce the plug-in height as a traumatic one:
"The decision set us back at least one year for the height decision required three major electro-mechanical component efforts in addition to the [[7000 series readout system|IC read-out effort]]: 1) new [[Back-lit switches|lit push-buttons]] ... we needed 25 on a panel; 2) [[cam switch]]es - these were Howard's ideas ... we needed them to be small and reasonably cheap; 3) [[Miniature relays|relays]] ... we needed them to be small and reliable. We then largely had to make do with other available parts, like potentiometers."
</blockquote>


[[Image:7000 slot pinout.jpg|thumb|500px|left]]


[[Category:Plug-in interfaces]]
[[Category:Plug-in interfaces]]
Retrieved from "https://w140.com/tekwiki/wiki/Special:MobileDiff/68960...91424"