The move follows nuisance calls research that found 37 per cent of consumers are unacceptably inconvenienced by silent calls and 22 per cent feel anxious when they receive them. Some 64 per cent of TPS registrants are also unacceptably inconvenienced by silent calls.
John Price, chairman of the DMA Contact Centre & Telemarketing Council and director of Brookmead Consulting, which undertook the research said: "The problem is that people getting silent calls don't know where they're coming from."
The new code states that DMA members must use a DMA-registered caller line identity. This allows people receiving silent calls to phone back, find out who called them and ask not to be contacted again.
The DMA is currently working with regulator Ofcom to reduce the number of silent calls. According to Price, seven firms are under investigation, including four DMA members.
Price will address the silent calls issue at the DMA's Return to the Welcome Call conference on 26 July. He will also focus on recorded messages and the rise of TPS registrations.
"We want to show everyone that we are finding a solution, rather than letting telemarketing be ground to dust," he said.