Network search/selection algorithm implemented on PXS8 module depends on the setting done by AT^SCFG command and parameter "MEopMode/AccT". In case selected technology is:

• “GSM/UMTS” – standard network selection algorithm applies
• “cdma2000“ - standard network selection algorithm applies
• “MULTIMODE“ – more complex network selection algorithm applies as described below

In case when “MULTIMODE“ is selected, a valid USIM is present and enabled (see SCFG command, parameter <SimIfAvail>) following set of rules applies.

Same rules apply in case when service is lost (no signal coverage etc.).

The power-up algorithm objective is to acquire the most preferred system that is available in the location where the MS is powering up as soon as possible. It is done in following steps where step1 has highes and step 4 lowest priority.

1. MRU – most to least recent used network/technology
2. GEO - set of network priorities for each geographic region defined by operator
3. PRL – list of all primarily 3GPP2 technology providers
4. PLMN database – If no GSM records are specified in the PRL.

The ordering of the technologies is determined by the most recent MRU entry. The MS may alternate between 1X and GSM searches before all systems within a given technology have been searched.

After 1st power-up (initial power-up when modules leave the factory), module will try to acquire CDMA first. If this is not possible, it will try to acquire 3GPP service.

MRU - The Most Recently Used (MRU) table is a mechanism that enables the MS to remember the most recently used systems on
which service was provided. The MRU is able to store the information of all systems, 1X and GSM. 

GEO - Operators shall be able to specify a unique set of network priorities for each geographic region. The area that each
GEO covers is operator-dependent and can range from a size of a single campus to an entire country. GEO segmentation enables
operators to optimize the Better Service Reselection (BSR) process by listing competing networks (and their corresponding
acquisition parameters) only in relevant geographical regions. 

PRL - The PRL is a data structure that is set up by the operator. It instructs the MS where to look for service and, when a
system is acquired, whether it is usable. In addition, the PRL specifies the relative priorities of the systems. While primarily
used for 3GPP2 system selection, the PRL can be extended to support GSM systems.

Regards

ALopez