In some cases, you have to reset the parity because the system that you are calling checks port parity and drops the line if it is wrong. The expect-send couplet ~~ P_ZERO sets parity to zero:
foo =,-, "" P_ZERO "" \dA\pTE1V1X1Q0S2=255S12=255\r\c OK\r\EATDT\T\r\c CONNECT |
In the same manner, P_EVEN sets it to even (the default); P_ODD sets it to odd; and P_ONE sets it to one. This pseudo-send string can also be used in entries in the Systems file.