Specifications

AN93
106 Rev. 0.8
Type II Caller ID/SAS Detection
When a call is in progress, the Subscriber Alerting Signal (SAS) tone is sent by the central office to indicate a
second incoming call. The central office may also issue a CPE Alert Signal (CAS) after the SAS to indicate that call
waiting caller ID (CWCID) information is available. If properly configured, the modem will acknowledge the CAS
tone, receive the CWCID data, and perform a retrain.
The Si24xx is configured through the +PCW command to toggle the RI pin (+PCW=0), hang-up (+PCW=1), or do
nothing (+PCW=2) upon receipt of the SAS tone. The default is to ignore the SAS tone. The modem, enabled
through the +VCID command, will collect caller ID information if +PCW is set to toggle the RI pin. The AT:I
command can be used to verify receipt of the SAS and CWCID data. Bit 9 will be set for SAS receipt due to the RI
toggle. Bit 4 will be set if CWCID data is received.
The CWCID data is collected using the +VCIDR? command. The data message is displayed in hexadecimal format
using ASCII text. The modem will return NO DATA if no caller ID is available. The +VCIDR response is listed below
for the following example CWCID message:
Date & Time: 09/11 16:21
ICLID Number:512-555-1234
Calling Name:JOHN_DOE
+VCIDR:
80 20 01 08 30 39 31 31 31 36 32 31 02 0A 35 31
32 35 35 35 31 32 33 34 07 08 4A 4F 48 4E 5F 44
4F 45 40
OK
Table 80 defines the Multiple Data Message Format (MDMF) parameters in the example response.
Table 80. MDMF Parameters
Character Description Hex Value ASCII Value
Message Type (MDMF) 80
Message Length 20
Parameter Type (Date/Time) 01
Parameter Length 08
Month 30 39 09
Day 31 31 11
Hour 31 36 16
Minutes 32 31 21
Parameter Type (Number) 02
Parameter Length 0A
Number 35 31 32 35 35 35 31 32 33 34 5125551234
Parameter Type (Name) 07
Parameter Length 08
Name 4A 4F 48 4E 5F 44 4F 45 JOHN_DOE
Checksum 40