I'm trying to get an analog phone attached to a handytone to do DTMF transfers. for example, *01 to park in slot 1 or *11 to pickup. Seems that the ATA doesn't handle this well. Anyone figured out a trick?
Most ATAs require a "flash", you then get dialtone, then then enter the "short code". The codes can usually be defined, in a table, in the device. It all depends on how the device interprets the star code, and if that is changeable.
Going back about 9 years, I realized had a similar problem with an SPA-2102 ATA. Finally figured out that it required the use of a blind transfer code before the park code. So...flash, 9801 (with *98 the blind transfer short code in the Linksys ATA). You would have to confirm the code used by the Grandstream, it may or may not be the same.
Doing a "regular" blind transfer from the same ATA is...*98201, which transfers to ext 201