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D-SUB Connector puzzle

R

Robert Latest

Jan 1, 1970
0
Hey guys,

this is a rather academic question because a few tens of microns don't
matter much with those old clunkers, but still this got me puzzled:

Looking at datasheets of D-SUB Connectores from different manufacturers,
I find three different inter-pin distances along the rows:

ERNI: 2.75mm
Harting: 2.74mm for 9 and 15 pin connectors, 2.76 for the others.
Deltron: 2.74mm
FCT: 2.74mm

The inter-row distance seems to be consistently 2.84mm.

All of course are supposed to be according to the same DIN/ISO standard.
Then there is the "US" and the "European" footprint, but I think the
difference is the distance between the PCB holes and the front panel
plane for the angled connectors.

I wonder if it is really true that the 9/15 pin plugs have an
ever-so-slightly different pitch than the others. Who comes up with
ideas like that?

robert
 
M

martin griffith

Jan 1, 1970
0
Hey guys,

this is a rather academic question because a few tens of microns don't
matter much with those old clunkers, but still this got me puzzled:

Looking at datasheets of D-SUB Connectores from different manufacturers,
I find three different inter-pin distances along the rows:

ERNI: 2.75mm
Harting: 2.74mm for 9 and 15 pin connectors, 2.76 for the others.
Deltron: 2.74mm
FCT: 2.74mm

The inter-row distance seems to be consistently 2.84mm.

All of course are supposed to be according to the same DIN/ISO standard.
Then there is the "US" and the "European" footprint, but I think the
difference is the distance between the PCB holes and the front panel
plane for the angled connectors.

I wonder if it is really true that the 9/15 pin plugs have an
ever-so-slightly different pitch than the others. Who comes up with
ideas like that?

robert
Could it be that the original D type was in imperial inches, rather
than metric, and there are rounding errors?


martin
 
S

Spehro Pefhany

Jan 1, 1970
0
Hey guys,

this is a rather academic question because a few tens of microns don't
matter much with those old clunkers, but still this got me puzzled:

Looking at datasheets of D-SUB Connectores from different manufacturers,
I find three different inter-pin distances along the rows:

ERNI: 2.75mm
Harting: 2.74mm for 9 and 15 pin connectors, 2.76 for the others.
Deltron: 2.74mm
FCT: 2.74mm

The inter-row distance seems to be consistently 2.84mm.

All of course are supposed to be according to the same DIN/ISO standard.
Then there is the "US" and the "European" footprint, but I think the
difference is the distance between the PCB holes and the front panel
plane for the angled connectors.

I wonder if it is really true that the 9/15 pin plugs have an
ever-so-slightly different pitch than the others. Who comes up with
ideas like that?

robert

I got the impression they designed the outer dimensions first and then
just divided by the number of pins minus one to get the exact pitch,
but I could be wrong about that... Originally they were cable
connectors and most users wouldn't have known or cared much about the
exact pitch.


Best regards,
Spehro Pefhany
 
A

Alan

Jan 1, 1970
0
I got the impression they designed the outer dimensions first and then
just divided by the number of pins minus one to get the exact pitch,
but I could be wrong about that... Originally they were cable
connectors and most users wouldn't have known or cared much about the
exact pitch.
I always understood that the 25 way connector was designed to have a
distance of 1.3 inches between the centres of the end pins on the 13
way side thereby giving a spacing of 0.1083(recurring)inches or approx
2.75mm.

I have seen it surmised that the original specifier(s)/committee made
a boo boo by making the original end to end measurement 1.3 inches
(for 13 pins) instead of 1.2 inches, which would have a made it a nice
0.1inch spacing.

Alan
 
S

Spehro Pefhany

Jan 1, 1970
0
Could it be that the original D type was in imperial inches, rather
than metric, and there are rounding errors?


martin

More likely it was in US inches.


Best regards,
Spehro Pefhany
 
F

Frank Bemelman

Jan 1, 1970
0
Spehro Pefhany said:
More likely it was in US inches.

2.75mm ~ 13/120 inch. Strange choice.

The russians made/copied many TTL 74xx chips, with partnumbers
like K155. I was surprised when I discovered these have a pitch of
2.5mm, not 2.54mm. You can still squeeze them in 2.54 sockets,
but with a 24 pin dip it really starts to hurt.
 
M

mkaras

Jan 1, 1970
0
Robert said:
Hey guys,

this is a rather academic question because a few tens of microns don't
matter much with those old clunkers, but still this got me puzzled:

Looking at datasheets of D-SUB Connectores from different manufacturers,
I find three different inter-pin distances along the rows:

ERNI: 2.75mm
Harting: 2.74mm for 9 and 15 pin connectors, 2.76 for the others.
Deltron: 2.74mm
FCT: 2.74mm

The inter-row distance seems to be consistently 2.84mm.

All of course are supposed to be according to the same DIN/ISO standard.
Then there is the "US" and the "European" footprint, but I think the
difference is the distance between the PCB holes and the front panel
plane for the angled connectors.

I wonder if it is really true that the 9/15 pin plugs have an
ever-so-slightly different pitch than the others. Who comes up with
ideas like that?

robert

For years I have worked with the D-Sub type connectors. The pin to pin
spacing in the rows has typically been 0.109 inches. That said the
mechanical drawings for the D-Subs from Amphenol (one of the original
manufacturers for D_Subs along with ITT Cannon) show that the pin to
pin center spacing for shell sizes E and A are 0.108 inches and are
0.109 for shell sizes B, C, and D. The row to row spacing has always
been 0.112 inches. Any other dimensional info you will see in the mm
realm is typically round-off error.

Many of the mechanical drawings I have referenced for D-Sub connectors
from manufacturers do not specify the total dimension between the
outside pins of the long row of pins. The prints are drawn in an manner
where the center to center of the jack screw holes are specified. The
connector pin pattern is then dimensioned to be centered either way
from the center of the jack screw to jack screw holes.

- mkaras
 
A

Adrian Jansen

Jan 1, 1970
0
Frank said:
The russians made/copied many TTL 74xx chips, with partnumbers
like K155. I was surprised when I discovered these have a pitch of
2.5mm, not 2.54mm. You can still squeeze them in 2.54 sockets,
but with a 24 pin dip it really starts to hurt.
European IC makers used a 'standard' pitch of 2.52 mm for quite a while,
to accomodate both 2.50 and 2.54 mm. Their intention was presumably to
eventually replace 2.54 with 2.50.

--
Regards,

Adrian Jansen adrianjansen at internode dot on dot net
Design Engineer J & K Micro Systems
Microcomputer solutions for industrial control
Note reply address is invalid, convert address above to machine form.
 
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