15.1.1.2. Notes for SIP device as OpenScape Mobile Pro Client Deskphone 
1. DTMF on SIP is possible via CSTA_GENERATE_DIGITS_REQUEST
2. HOLD from OpenScape Mobile Pro Client when call is on the desk
phone
SIP-UFIP as DESK feature: CSTA HOLD implemented for SIP-UFIP as DESK
- CSTA HOLD is an exclusive RMX-CP feature (it is not a device feature)
- If CSTA HOLD is invoked, then only CSTA RETRIEVE is allowed to reconnect
- If SIP HOLD is invoked, then only SIP RETRIEVE is allowed to reconnect
- If CSTA HOLD is invoked, then SIP phone is not notified (device itself is not aware that its partner is in HOLD). In this case SIP phone, has HOLD option in phone menu, but if user selects this option it is rejected. The same happens for NEW CALL and TRANSFER options which use HOLD as first step
3. RETRIEVE from OpenScape Mobile Pro Client when call is on the deskphone SIP-UFIP as DESK feature: CSTA RETRIEVE implemented for SIP-UFIP as DESK- CSTA RETRIEVE is an exclusive RMX-CP feature (it is not a device feature)
- If CSTA HOLD is invoked, then only CSTA RETRIEVE is allowed to reconnect
- If SIP HOLD is invoked, then only SIP RETRIEVE is allowed to reconnect
4. Message waiting call back is not supported for SIP devices.5. Move call to OOS UFIP deskphone Move call to desktop appears when OOS status of SIP-UFIP deskphone is not visible in the system (check AMO SDSU). The system relies on a mechanism implemented in the gateway which reports OOS status of SIP. This mechanism does not present this status in real time, therefore there are cases where the SIP phone is OOS but the systen is not aware of this.IMPORTANT:
Actions initiated from OpenScape Mobile Pro Client (via CSTA) should not be mixed with actions initiated from SIP-UFIP phone, or the other way around. It is recommended to use only OpenScape Mobile Pro Client actions (via CSTA) or only physical actions from SIP-UFIP phone.