Specifications

AN93
Rev. 0.8 89
U7A (GENA)
U7A is a bit-mapped register. U7A resets to 0x0000.
Bits 15:8 and 5:3 are reserved.
Bit 7 (DOP) is used in a method to determine whether a
phone line supports DTMF or pulse only dialing. See
"Pulse/Tone Dial Decision" on page 148 for details.
Bit 6 (ADD) attempts DTMF dial, then falls back to pulse
dialing if unsuccessful. First digit is dialed as DTMF. If a
dialtone is still present after two seconds, the Si2493/
57/34/15/04 redials the first digit and remaining digits as
pulse. If a dialtone is not present after two seconds, the
Si2493/57/34/15/04 dials the remaining digits as DTMF.
Bit 1 (HDLC) controls whether the normal asynchronous
mode (default) is used or the transparent HDLC mode is
enabled. (See "Legacy Synchronous DCE Mode/V.80
Synchronous Access Mode" on page 20 for more details
on these modes.)
Bit 0 controls whether the normal ITU/Bellcore modem
handshake (default) or a special fast connect
handshake is used. Fast connect is typically used in
specialized applications such as point-of-sale terminals
where it is important to rapidly connect and transfer a
small amount of data. (See Table 66.)
Table 66. U7A Bit Map
Bit Name Function
15:8 Reserved Read returns zero.
7DOP0 = Normal ATDTW operation.
1 = Use ATDTW for pulse/tone dial detection (see "Pulse/Tone Dial Decision" on page 148
for details).
6ADDAdaptive Dialing.
1 = Enable
0=Disable
5:3 Reserved Read returns zero.
2 Reserved Read returns zero.
1HDLCSynchronous Mode.
0 = Normal asynchronous mode.
1 = Transparent HDLC mode.*
0 FAST Fast Connect.
0 = Normal modem handshake timing per ITU/Bellcore standards.
1 = Fast connect modem handshake timing.*
*Note: When HDLC or FAST is set, the \N0 (Wire mode) setting must be used.