Abstract: An optoelectronic module includes a housing enclosing at least one optical transmitter or receiver and includes a release mechanism configured to engage with a cage sized and shaped to receive the housing. A cable connector for a fiber optic cable is configured to engage in a port of the module, and a slideable collar on the cable connector can keep the module engaged in the port. For example, the collar can hold tabs or arms inside the port engaged with slots or indents on a body of the connector to prevent the connector from being pulled from the port. A retainer is configured to prevent retraction of a collar on the cable connector so that the connector is not inadvertently removed from the port. By keeping the connector engaged, the retainer may by extension keep the module engaged in the cage by preventing inadvertent release of the release mechanism on the module.