850/900/2100 help!

[taotoo]

If I buy a phone that can do:

GSM 850 900 1800 1900

HSPA+ 850 2100

...could it be used for 3G data on both CAT 850 and AIS 2100?

If so, when using AIS and 2100 happens to not be available, is there an AIS 900 3G network that the phone wouldn't be able to fall back to due to the missing 3G frequency (so would end up with GPRS/EDGE instead)?

[dddave]

It appears that most 2 SIM phones currently being sold can only use one 3G or 4G SIM at a time for high speed data while the secondary SIM is relegated to 2G.

There may be some phones out there that can use both SIMs for high speed data but I haven't seen any mention of them.

[RichCor]

...could it be used for 3G data on both CAT 850 and AIS 2100?

Yes.

My CAT, Truemove-H and DTAC on UMTS/HSPA 850

AIS, DTAC, TOT 3G on UMTS/HSPA 2100

If so, when using AIS and 2100 happens to not be available, is there an AIS 900 3G network that the phone wouldn't be able to fall back to due to the missing 3G frequency (so would end up with GPRS/EDGE instead)?

Correct.

If the AIS SIM is enabled and no 3G network can be found the SIM will allow the phone to use the GSM/2G chipset to connect, and limiting your connection to 2G speeds.

Some Dual-SIM phones allow you switch which SIM is used to provide 3G Data Connections when both SIMs are enabled (so if 3G isn't available you can manually switch 3G providers to grab a 3G Data Connection off the alternate SIM network)

A few Dual-SIM phones even allow you to enable both SIMS 3G Data Connections simultaneously.

[taotoo]

It appears that most 2 SIM phones currently being sold can only use one 3G or 4G SIM at a time for high speed data while the secondary SIM is relegated to 2G.

There may be some phones out there that can use both SIMs for high speed data but I haven't seen any mention of them.

Thanks - I should have been clearer, I wasn't planning on running both sims together - just wondered about the possibility of switching networks but retaining the same phone.

...could it be used for 3G data on both CAT 850 and AIS 2100?

Yes.

My CAT, Truemove-H and DTAC on UMTS/HSPA 850

AIS, DTAC, TOT 3G on UMTS/HSPA 2100

If so, when using AIS and 2100 happens to not be available, is there an AIS 900 3G network that the phone wouldn't be able to fall back to due to the missing 3G frequency (so would end up with GPRS/EDGE instead)?

Correct.

If the AIS SIM is enabled and no 3G network can be found the SIM will allow the phone to use the GSM/2G chipset to connect, and limiting your connection to 2G speeds.

Some Dual-SIM phones allow you switch which SIM is used to provide 3G Data Connections when both SIMs are enabled (so if 3G isn't available you can manually switch 3G providers to grab a 3G Data Connection off the alternate SIM network)

A few Dual-SIM phones even allow you to enable both SIMS 3G Data Connections simultaneously.

Excellent - that's just what I wanted to know - thanks v much.

[regn]

DTAC start now with Trinet to use also 2100 Mhz for 3G. My Phone cannot run on 850 MHz. But the coverage list of DTAC make no distinguishing between 2100 and 850. So, does anybody know, if 2100 is supported on most cells? or just on some few?

[RichCor]

DTAC start now with Trinet to use also 2100 Mhz for 3G. My Phone cannot run on 850 MHz. But the coverage list of DTAC make no distinguishing between 2100 and 850. So, does anybody know, if 2100 is supported on most cells? or just on some few?

Not all DTAC towers will service 2100. Many of the 11,000 850MHz towers were leased from CAT, but DTAC is now branching out independently with new towers.

21 May 2015

DTAC received an order from the Central Administrative Court to cease installation or connection of its 2100MHz 3G/4G infrastructure which it operates under a full facilities-based (Type 3) licence but which also shares connectivity and physical sites with the original build-transfer-operate (BTO) concession issued by CAT.

14 August 2015

AIS and dtac TriNet announce their partnership to share telecommunication towers to improve quality and increase efficiency of their services nationwide. ... each contributing 1,000 towers (2,000 total) before the end of this year. Most of the shared towers are in the provinces. ... Late last year, DTAC TriNet co-signed an agreement with the True Telecommunications Growth Infrastructure Fund (TRUEGIF) for the initial lease of more than 100 telecom towers.

TowerExchange issue #14: A guide to the Thai telecom tower market

Hey, you asked.