If you include the line-protocol x.21 statement, the following statements are invalid:
- dce-options | dte-options {
- cts (ignore | normal | require);
- dcd (ignore | normal | require);
- dsr (ignore | normal | require);
- dtr (assert | de-assert | normal);
- rts (assert | de-assert | normal);
- tm (ignore | normal | require);
- }
- clocking-mode (dce | dte);
- cts-polarity (negative | positive);
- dce-polarity (negative | positive);
- dsr-polarity (negative | positive);
- dtr-circuit (balanced | unbalanced);
- dtr-polarity (negative | positive);
- loopback (dce-local | dce-remote);
- rts-polarity (negative | positive);
- tm-polarity (negative | positive);
You can include the line-protocol statement at the following hierarchy levels: