Mobile payment startup Square has begun shipping its iPhone 4-compatible credit card reader, replacing an older model whose metal headphone jack fitting apparently interferes with the handset’s notoriously finicky antenna. According to the company — cofounded by Twitter co-founded Jack Dorsey — anyone who has recently used the Square app on an iPhone 4 will automatically be sent this latest dongle, which replaces the metal housing with a plastic one. Square also offers a version of its reader for iPad tablets.
Since announcing its intentions in October of last year, Square has seen a number of competitors enter the smartphone payment terminal game, including VeriFone and the hardware/software team of Intuit and mophie. We also recently saw a device-agnostic solution in the form of QuickPay’s ROAMpay, which brings payment-processing capabilities to certain BlackBerry and Android devices in addition to the usual iPhone compatibility.