Northern UTA220/UTA220k - Manual (Page 108)

12-32
UTA220/UTA220k
D-Channel X.25
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.
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.
Table 12-26: Echo Mask
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 *