The following is a list WND2200 service:

SIM Card detection problem
Purpose:
Troubleshooting failure to detect SIM card resulting in “Insert SIM”, or “Invalid SIM” message display on Wind Duo2200.

Reason:

1. Unstable contact between the SIM Card & the SIM socket of the handset.
2. Handset does not receive required information (IMSI) due to abnormal  network conditions.
3. TDMA noise carries on SIM interface signal.

Details:

1. The card inserted might slightly move inside the socket due to a mechanical shock.
2. This might rarely occur and is displayed by other brands as “Network Failure”.  We have experienced such a situation when the phone is being used (talk-on-the-phone) or idle in areas where there are frequent changes in electrical fields such as in downtown Phnom Penh. In such circumstances and when transmitting (TX) at max power, there is a slight probability for the SIM interface, thus producing negative effects on the SIM signals such as SIMVCC & SIMIO / SIMCLK

Universal connector:
Purpose:
To avoid units shutdown when connecting TA (chargers).

Reason:
PIN 1 is touching the ground body of the jack while inserting TA connector.

Details:
We have identified that some of our preproduction units might suddenly shutdown when a TA (charger) connector is inserted in an angled position. (Not straight) and will not power on again even if the reset button is pushed, unless the battery is removed and inserted again.