Fender Musical Instruments Corp. hopes to hit a high note with shoppers this summer by letting them to get a free messenger bag and amplifier cable after a purchase. Direct digital marketing firm Knotice Ltd. is providing the text technology that links customers wherever they may be to Fender’s web servers.

Shoppers who buy one of Fender’s Hot Rod amplifiers can get the free gifts by registering online, downloading a form and mailing it to Fender or by texting a keyword to  Fender’s short code placed on qualifying products to register the purchase . A short code is a truncated phone number that consists of five or six numbers used by companies in marketing materials.

Shoppers text “Tune Up” to the Fender short code. A reply message requests the buyer’s e-mail address and provides further instructions. Other information collected includes a unique product identification code, the buyer’s address, where the amplifier was bought and the name of the buyer. The promotion expires July 31.

The text message method to complete the gift form can be quicker than filling out a paper form and mailing it in, Knotice says.

Fender’s use of text message marketing is part of a larger trend among companies. In March, Forrester Research Inc. reported nearly 53% of interactive marketers intend to increase their mobile commerce budgets in 2011.