ATDB1 | use B1 channel in Originate mode. |
ATDB2 | use B2 channel in Originate mode. |
ATDB3 | use both B1 and B2 channels in Originate mode. |
ATAB1 | use B1 channel in Answer mode. |
ATAB2 | use B2 channel in Answer mode. |
ATAB3 | use both B1 and B2 channels in Answer mode. |
92 Advanced ISDN Call Control