User's Manual

AT Command Set
MC35_ATC_01_V04.00 Page 74 of 238 02.04.2002
4.15 AT+CGSN Request product serial number identification (IMEI) identical
to GSN
Test command
AT+CGSN=?
Response
OK
Execute command
AT+CGSN
Response
TA returns identification text for determination of the individual ME.
<sn> OK
Parameter
<sn> IMEI of the telephone (International Mobile station Equipment Identity)
Reference
GSM 07.07
Note
See also ”AT+GSN Request TA serial number identification”.
4.16 AT+CHLD Call hold and multiparty
Test command
AT+CHLD=?
Response
+CHLD: (list of supported <n>s)
OK
Execute command
AT+CHLD=[<n>]
Response
TA controls the supplementary services Call Hold, MultiParty and Explicit Call
Transfer. Calls can be put on hold, recovered, released, added to conversation
and transferred.
Note: Supplementary services are only applicable to teleservice 11 (Speech tele-
phony).
OK
If error is related to ME functionality:
+CME ERROR: <err>
Parameter
<n> 0 Terminate all held calls; or set UDUB (User Determined User
Busy) for a waiting call, i.e. reject the waiting call.
1 Terminate all active calls (if any) and accept the other call
(waiting call or held call)
1X Terminate the active call X (X= 1-7)
2 Place all active calls on hold (if any) and accept the other call
(waiting call or held call) as the active call
2X Place all active calls except call X (X= 1-7) on hold
3 Add the held call to the active calls
Reference
GSM 07.07
Note
• In conflicting situations, e.g. when a waiting call comes while there are already
held calls, the above procedures apply to the waiting call only. For example,
<n>=0 rejects the waiting call, but does not affect the held calls.
• While the PDP context for GPRS is activated it is recommended to terminate
any calls with AT+CHLD=1 rather than usind ATH. This is significant because
ATH would also cancel an active PDP context. See also Chapters 2.12 and
6.3.2.