int tespecial; /* special TE-mode behavior */
int l1hold; /* hold layer 1 (1=on, 0=off) */
int l2hold; /* hold layer 2 (1=force, -1=disable, 0=default) */
+ int gsm; /* interface is an GSM interface */
int channel_force; /* forces channel by protocol */
int nodtmf; /* disables DTMF */
struct select_channel *out_channel; /* list of channels to select */