Staying Connected - December 2011

Custom or Off-The Shelf Medical Connectors

Custom low-profile connector for
ambulatory monitoring

When designing a new device, one of the decisions that medical equipment manufacturers are faced with is choosing a connector and mating receptacle.  For some applications, a standard or off-the-shelf connector is a good option.  For other applications, a custom or hybrid connector may offer a better solution.

Some of the reasons why a device manufacturer may consider a custom medical connector instead of an off-the-shelf connector are:

  • A unique design is required to assure that only a specific connector can be connected to the device
  • Connector shape needs to match the profile of the device
  • A single connector must interconnect a variety of signal types (high voltage, low voltage, high bandwidth)
  • An off-the-shelf connector is may not meet the cost target
  • Custom logo or markings on the connector are desired or required
  • Lead-time for an off-the-shelf connectors may be unacceptably long

A custom connector design can enhance safety.  Unique pin-to-socket patterns or connector shape can prevent mating by incompatible connectors.

Custom 11 contact connector

Custom connector fits contour
of device case

With a custom connector solution, design and tooling fabrications costs are generally incurred.  These up-front charges can be a roadblock to choosing a custom connector solution.  However, once design and tooling are complete, a custom connector can often cost much less than off-the-shelf connectors.

Physical Properties

With a custom connector solution, each desired physical property can be addressed.  A custom connector can be designed so that mate and un-mate force matches specific customer requirements.  This force is composed of the friction from each pin and socket as well as the mechanical interface of the connector and receptacle.  Employing a “tool safe” design allows the final force to be “dialed in” with minor tool modifications to give the exact feel desired.

Moisture protection is often a consideration in medical interconnect systems.  Off-the-shelf connectors typically incorporate shells and pre-molded boots or collars.  When these components are assembled into a finished connector, they typically do not offer a high degree of ingress protection.  Custom overmolded connectors can be designed with any required ingress protection (IP) rating.

Standard boots typically do not provide
high levels of ingress protection

Custom connector designed to meet
IP67 rating either mated or unmated

Availability of connectors from major suppliers can also be an issue with lead times of 8-16 weeks being common.  Once tooling has been fabricated, the lead time for custom connectors can be much shorter than for off-the-shelf connectors.

Design Input Requirements

Establishing design requirements is one of the first steps in determining whether a custom or standard connector is the best option.  Factors that may be considered include:

  • Number and type of contacts (pins or sockets and specifications for each)
  • Cable configuration (ECG, defib, power, analog, digital, bandwidth, pneumatic, fiber optic, or combination of one or more.)
  • Cable diameter, material and shape
  • Strain relief
  • Shielding requirements for both connectors and cable
  • Voltage and current requirements
  • Size constraints and/or desired physical size
  • Ingress protection (IP) requirements or rating
  • Number of mate and un-mate cycles required
  • Locking mechanism – if any
  • Keying requirements
  • Desired mate and un-mate force
  • Cleaning and sterilization requirements
  • Standards and regulatory compliance
  • Logos, markings and serialization

Custom keyway prevents non-keyed connector from being plugged
into DB-style receptacle

Custom connector with OEM logo

Custom Connector Components

A custom connector typically involves an injection molded hard plastic insulator into which pins, sockets or both are inserted.  Termination of conductors to the pins or sockets by solder or crimp is most common.  This assembly is then overmolded with a rigid material such as polypropylene which holds the construction together and provides physical strength.  A second overmolding with a material such as a thermoplastic elastomer gives the connector the desired color, finish, look and feel.

Hybrid Connectors

For some applications, a hybrid connector may be the best option.  A hybrid connector is an off-the-shelf connector with custom features such as an overmolded grip or strain relief.  Design and tooling costs for a hybrid connector can be less than for a custom connector yet the finished product can have the look, feel, and some of the additional performance advantages of a custom connector.  Besides lower engineering costs, a hybrid connector can have a shorter design and development schedule than a fully custom connector design.

Off-the-shelf connector with custom
overmolded bend relief

3M MDR connector with custom
angled overmolded strain relief

Freedom From Legacy Designs

Affinity is in a unique position when compared to the connector manufacturers.  Because we are not a connector company, we routinely incorporate connectors from all major manufactures into our products if this option best matches our customers design requirements.  Since we are not constrained by legacy designs, we are free to create an entirely new connector when a unique interface is required.

Example of a custom in-line
21-contact connector design

Custom plug and receptacle


A custom or hybrid connector can provide unique features and benefits for medical devices requiring an interconnect system.  Safety and reliability can be enhanced and a custom connector may be a more cost effective solution.

Whether you need a custom connector, an off-the-shelf connector or a hybrid connector, we can help.  Affinity Medical Technologies has experience and expertise in designing and manufacturing custom medical connectors and cable assemblies.  Contact Affinity at 949-477-9495 or email to

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Christmas Gift Suggestions

Christmas is celebrated as both a religious and secular holiday around the world.  One of the traditions of Christmas and winter holidays is gifts.  Often finding a suitable gift that the recipient will appreciate is difficult and frustrating.  We offer here, some unique gift suggestions:

10-Lead ECG Cable – This gift suggestion is a “top-of-the-line” 10-lead ECG cable.  This is a robust, heavy duty cable that will provide years of service.  Whoever receives this gift will be able to proudly show their cable to family and friends.

5-Lead Telemetry Cable – A telemetry cable makes a unique gift for those with a limited budget.  This telemetry cable features five 18” snap leads, each with an embedded defibrillation protection resistor.  This cable is available in both AHA and IEC compliant version.

A 10-lead ECG cable will certainly
make a unique gift

This five-lead telemetry cable makes
a wonderful and inexpensive gift

Mold Tooling – What a wonderful gift for the person who “has everything!”  Mold tooling can be prominently displayed on a coffee table, book case or curio cabinet.  It is sure to attract attention and will be a conversation piece for years to come.

Stocking-Stuffer – This simple, two-lead cable is the perfect “stocking-stuffer.”  It features a medical-grade push-pull connector with overmolded strain relief on one end and snap leads on the opposite end.

A gift of mold tooling is unique and will be
appreciated for years to come

This inexpensive cable assembly makes
a unique “stocking stuffer"

While none of these gifts are actually available for sale, we thought you might get a laugh at what a cable manufacture thinks is the “perfect gift!”

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Announcements, Information and Trivia

Happy Holidays from the Affinity team

As 2011 ends the entire Affinity team wishes you and your family the Happiest of Holidays and a happy, healthy and prosperous New Year!

Winter Trivia

Ten inches of snow is approximately equal to one inch of rain.

While water freezes at 32˚F (0˚C), it takes time for water to freeze at this temperature.  Water freezes spontaneously at -40˚F (also -40˚C).

Water freezes
spontaneously at -40

The lowest temperatures
recorded on earth have
been in Antarctica

Winter Solstice will occur on December 22, 2011 at 05:30 UTC.  The sun is directly overhead on the Tropic of Capricorn in the southern hemisphere.

The lowest temperature ever recorded at the surface of the Earth was -128˚F (-89˚C) Russia’s Vostok Station in Antarctica on July 21, 1983.

Absolute zero in terms of temperature is -459.7˚F (-273.15˚C).