The JamCam - Jam Online - JamOnline - KB Gear - Multimedia MMC DRAM vs SDRAM Memory Cards

USING AN SDRAM (Secure Digital Memory Card) INSTEAD OF A DRAM MMC (Digital MultiMedia Memory Card) in the Model 3.0 JamCam digital camera IS NOT RECOMMENDED but, with modification, the 3.0 JamCam can use the SDRAM memory card.

How to quickly identify a MultiMedia MMC Card and a Secure Digital SD Memory Card

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MMC (MultiMedia DRAM) Card
The card is identified as a MultiMedia Card on the label. No interlock or write-protect switch is available on the MultiMedia Card. MultiMedia Memory Cards use seven electrical connectors (the shiny metal seams at the top of the card) to transfer information from the card to the camera and vice-versa.

Secure Digital (SDRAM) Card
The label identifies the card as Secure Digital. A write-protect device is available on the left side of the SD card and an interlock is on the right side. The SD card uses nine electrical connections. The two additional connectors are used for the SD card write-protection features.

JamCam user ' Xperience' has posted a modification to the JamCam that will allow the JamCam to use an SDRAM Memory Card in place of a DRAM MultiMedia Memory Card (see the posting GETTING SECURE DIGITAL MEMORY CARDS TO WORK IN JAMCAM in the MODIFYING THE JAMCAM forum).

The Model 3.0 JamCam camera is an older 2nd generation digital camera and, as such, REQUIRES the use of an optional DRAM MultiMedia Memory Card (MMC) to store extra photos that exceed the JamCam's 4MB internal memory. Many JamCam users have mistakenly purchased an SDRAM Memory Card for use in the JamCam instead of the DRAM MultiMedia card. The use of a SDRAM Memory Card in the JamCam instead of a DRAM MMC card may lead to problems (see the posting MMC CARD NOT RECOGNIZED BY JAMCAM in the MOST COMMON JAMCAM QUERIES FORUM). Reguardless of what a camera shop tells you, an SDRAM Memory Card and a DRAM MMC Memory Card ARE NOT EXACTLY THE SAME THING when it comes to the JamCam!!!

The SDRAM Memory Card is a little shorter in length, just a bit larger in width and slightly thicker (2.1mm vs 1.4mm) than a DRAM MMC Card. This difference is enought to sometimes cause a misalignment when the card is inserted in the card slot and create a poor electrical connection between the JamCam memory card slot contacts and the memory card circuits. Also, the manufacturers of the SD Memory Card have squeezed 9 slightly narrower electrical connections onto the card in place of the original 7 wider electrical connectors on the DRAM card. If the memory card is even slightly misaligned in the memory card slot the smaller contact surface area can result in a poor electrical connection between the JamCam and the SDRAM Memory Card causing either complete or partial photo download failure. The photo below illustrates how, due to the narrowness of the 'READ' and 'MEMORY' fingers, even a slight misalignment of the SD card can result in a poor electrical connection.

A poor electrical connection can result in the failure of the Jamcam to recognize additional memory or to properly format/reformat the memory card. If this condition exists the JamCam may indicate it is storing photos beyond its internal memory capacity storage but, in actuality, it is not. These pictures will be lost, only the photos stored in the JamCams internal memory will be downloaded. Another condition that may arise from a poor memory card electrical contact condition is the failure of the JamCam to completly delete or erase stored photos from the memory card. Previously deleted photos may show up on a picture download, usually mixed in with or completely replacing photos shot at a later time. Note that the above conditions may still occur even if an MMC card is substituted after first trying an SD card - the insertion of the SD card into the memory card slot might have damaged or bent the camera electrical pin contacts.

Besides very slight physical size differences the two cards use different technology. The DRAM MMC card is a 1st generation memory card. It was expensive to produce, had a slow response time, was limited in its storage capacity but tended to retain its memory when left in an unpowered camera over a long period of time (eg. the camera is left in the closet for 6 months thereby depleting the battery).

The SDRAM Memory Card is the latest technology - cheaper to manufacture, has a faster response time, is almost unlimited in its storage capacity but can wipe its memory if left in the camera and the power source (battery) becomes exhausted. The memory wipe will not occur if the SDRAM Memory Card is removed before the camera is stored but accidental storage does happen.

Most newer digital cameras are reverse engineered for the use of both the SDRAM and DRAM memory cards. The JamCam, being an older camera, was not engineered to accept both types of memory cards mainly because SDRAM Memory Cards had not been developed at the time the JamCam was released to the consumer market.

Therefore it is recommended, unless the user desires to modify and use an SDRAM in the JamCam, that DRAM memory cards only be used in the Jamcam.