HBC Interface Box Installation Created with Sketch. The handset-based console interface boxes connects the handset-based console to the SRG3900/SCG22 and attaches to the HBC cradle. Find a partner More accessories ItemPart no.HBC Interface Box300-00670Compatible with these accessoriesPlease select one more product to compare with. Handset-Based Console 3 More details Please select one more product to compare with. SRG/SCG Hands-Free Kit (Console) More details Compatible with these productsPlease select one more product to compare with. SRG3900 More details Please select one more product to compare with. SCG22 More details