This object indicates the type of trunk
line to which the access-code is applied to.
The type of trunk lines can be fxo, e&m,
bri, and pri.
fxo - Enables a foreign exchange office (FXO)
interface.
em - Enables an analog ear and mouth (E&M)
interface.
bri - Enables a BRI interface.
pri - Enables a PRI interface.