Specifications

AN93
132 Rev. 0.9
3.5.17.2. Receiving Modem-On-Hold Requests
If Modem-on-hold is enabled via the +PMH=1
command, the Si2493 may be placed on hold by a
remote modem. The maximum time the modem will
remain on hold is configured with the +PMHT setting.
Possible values of +PMHT are given in Table 88. Upon
receipt of a Modem-on-hold request, the Si2493 will
indicate +PMHR: followed by the code corresponding to
the timeout granted. The DCD pin will de-assert while
the modem is on hold, and the CONNECT result code
will indicate a return to data mode. A modem disconnect
due to a timeout or failed negotiation will result in a NO
CARRIER result code.
3.5.18. V.92 Quick Connect
The Si2493 supports ITU-T V.92 shortened Phase 1
and Phase 2 to decrease the time required to connect to
a server modem using the V.90 modulation. After the
first call, the Si2493 will retain line parameters that allow
it to use shortened Phase 1 and 2 to reduce the total
negotiation time. If line conditions change or the remote
server does not support the shortening of these phases,
the modem will automatically connect with the normal
Phase 1 and Phase 2 negotiation unless specifically
commanded not to. Two AT commands control this
feature: AT+PQC and AT+PSS.
The AT+PQC command controls the enabling and
disabling of shortened Phase 1 and Phase 2 individually
according to Table 89. It is recommended that both
shortened phases be used to realize the maximum
reduction in connect time. The possible settings of the
AT+PSS command are shown in Table 90. The AT+PSS
command may be used to force quick connect by
setting AT+PSS = 1; however, this is not recommended
because calling a server that does not support this
feature will result in a failed connection.
Table 88. Possible +PMHT Settings
<Value> Description
0 Deny V.92 Modem-on-Hold Request
1 Grant MOH with 10 second timeout
2 Grant MOH with 20 second timeout
3 Grant MOH with 30 second timeout
4 Grant MOH with 40 second timeout
5 Grant MOH with 1 minute timeout
6 Grant MOH with 2 minute timeout
7 Grant MOH with 3 minute timeout
8 Grant MOH with 4 minute timeout
9 Grant MOH with 6 minute timeout
10 Grant MOH with 8 minute timeout
11 Grant MOH with 12 minute timeout
12 Grant MOH with 16 minute timeout
13 Grant MOH with indefinite timeout
Table 89. AT+PQC Parameters
<Value> Description
0 Enable Short Phase 1 and Short Phase 2
1 Enable Short Phase 1
2 Enable Short Phase 2
3 Disable Short Phase 1 and Short Phase 2