Someone

static const struct ast_channel_tech zap_tech = {
        .type = type,
        .description = tdesc,
        .capabilities = AST_FORMAT_SLINEAR | AST_FORMAT_ULAW,
        .requester = zt_request,
        .send_digit = zt_digit,
        .send_text = zt_sendtext,
        .call = zt_call,
        .hangup = zt_hangup,
        .answer = zt_answer,
        .read = zt_read,
        .write = zt_write,
        .bridge = zt_bridge,
        .exception = zt_exception,
        .indicate = zt_indicate,
        .fixup = zt_fixup,
        .setoption = zt_setoption,
};