A pin count is a useful starting filter for a D-SUB connector, but it does not describe the whole connection. Before selecting a PCB footprint or ordering a replacement, compare the contact arrangement, mating gender, orientation and termination. Each answers a different fit question.
Match the contact arrangement before the mounting style
Begin with the connector that your part must mate with. Record its contact arrangement and gender, then compare the mating face and fixing points on the drawings. If you are replacing a part, keep the existing part number and drawing revision with your selection notes.
A high-density connector needs its own contact-layout check. For example, RHT-681-1190 is a 44-pin female high-density D-SUB with a right-angle orientation and through-hole mounting. “44-pin” describes only one part of that specification; it does not replace the layout or mounting dimensions.
Combo arrangements need a more specific description than a total contact count. RHT-681-1222 has a 7W2 arrangement containing two large and five small contacts. For this part, use that arrangement when comparing the mating face. Do not reduce it to a generic seven-contact requirement.
Separate orientation from termination
Compare the direction of the mating connection with the board and enclosure layout. Then check how the connector attaches to the board or cable. Straight or right-angle orientation and through-hole or solder termination are separate selection details.
RHT-681-0402 is a straight, 9-pin male connector for through-hole PCB mounting. RHT-681-1158 is a right-angle, 15-pin male connector with machined pins and through-hole PCB mounting. Both use through-hole PCB mounting, but their pin counts and orientations differ. They illustrate different configurations, not interchangeable parts.
Check the PCB hole pattern, fixing points, connector position and clearance for the mating cable before releasing the board layout. For a replacement, compare those dimensions with the existing assembly as well as with the new connector drawing.
Use the complete configuration to narrow the shortlist
| Example | Contact configuration | Orientation | Mounting or termination |
|---|---|---|---|
| RHT-681-0402 | 9-pin male | Straight | Through-hole PCB mounting |
| RHT-681-1158 | 15-pin male; machined pins | Right-angle | Through-hole PCB mounting |
| RHT-681-1190 | 44-pin female; high-density | Right-angle | Through-hole mounting |
| RHT-681-1222 | 7W2 male; two large and five small contacts | Straight | Solder termination |
These examples show which details to compare; they do not establish a mating pair or a cross-reference. After narrowing the mechanical configuration, check the selected part’s electrical requirements and any required environmental protection against its applicable specifications.
For adapters, check the connections at both ends
With an adapter or gender changer, write down the interface and gender at each end separately. Check the required pin-to-pin connections as well as the external fit. Matching connector shapes alone does not establish the signal connections.
Keep the selection record specific
A useful record identifies the mating part, the contact arrangement, gender, orientation and termination, followed by the drawing revision and the dimensions that constrain the assembly. If a dimension or pin assignment has not been confirmed, identify that exact item. This makes the remaining engineering check clear without reopening the entire selection.
Compare D-SUB connectors by configuration, then open the individual product specifications for the shortlisted parts.