Parameter 20: Echo Mask
Parameter 20, in conjunction with parameter 2 set for character echo, specifies what characters are echoed by the PAD to the local DTE.
If parameter 20 bit 6 is set for echo of edit characters, but parameter 15 is set to 0 for no edit, the edit characters issued in the data transfer mode are not echoed. Also, since parameter 15 is set to 0 (no edit), no edit service signals are transmitted to the local DTE.
| Table |
|
|
Value | Description |
|
|
0 | No echo mask |
|
|
1 | No echo of CR |
|
|
2 | No echo of LF |
|
|
4 | No echo of VT, HT, and FF |
|
|
8 | No echo of BEL and BS |
|
|
16 | No echo of ESC and ENQ |
|
|
64 | No echo of edit characters as designated by parameters 16, 17, and |
| 18 * |
|
|
Parameter 20 can be any added combination of the above values. * default
Parameter 21: Parity Treatment
Parameter 21 specifies whether the PAD should check parity in the data stream from the local DTE and/or generate parity in the data stream to the local DTE. The AT command @P3 also allows parity checking to be enabled or disabled in the event that X.25 protocol is not in operation, and the protocol in operation is not capable of controlling parity checking. If X.25 is the active protocol, the setting of parameter 21 overrides the setting of the AT command @P3. The DTE word length and parity is automatically set when the terminal adapter receives an AT command prefix while in the AT command mode.
The PAD is only specified by CCITT to operate with 7 bit characters plus parity or 8 bit characters and no parity. If the user disables parity checking and generation, and the remote DTE disables parity checking and generation, be sure the remote DTE’s parity is the same as the local DTE’s parity. Otherwise, the incoming data transmitted to the local DTE is invalid; the remote DTE’s parity will not be stripped and will not match the local DTE’s parity.
UTA220/UTA220k |
