Comment Re:No Bluetooth (Score 5, Informative) 372
I used to work for AT&T Wireless. ALL GSM phones require a SIM card (Contains your Home SID, ICCID, MDN aka your phone#). TDMA phones require no SIM as they have an EEPROM built-in to store the NAM - Numerically Assigned Module (containg Home SID, ESN, MDN).
One multi-band phone (that is TDMA/GSM capable) actually requires a special SIM card for the dual functionality. This SIM module contains the EEPROM equivalent for the TDMA programming of the phone separate from the GSM side of the SIM. This is the Sony T26U (it also utilizes Analog towers too). This a true GSM phone with a TDMA overlay. The Siemans S46 has a built in ROM and uses a SIM, this is a TDMA phone with a GSM overlay.
But all GSM phones require a SIM card, this is not only a spec for the GSM network, but if a GSM phone (assuming multi-band, ie. Siemans S46) is running without a SIM, it would only run in TDMA mode, and if not a multi-band, it would not complete its "power up" to an operational state; it would error and demand a SIM to be entered. The Sony T62U will not function without a SIM.
Most GSM phones are NOT multi-band. They would therefor require a SIM. Multi-band phones generally don't come with the "eye candy" that other phones do (ie. Cam, Colour, Blue Tooth). These are more for people who need a phone to be a phone all the time (best coverage over multiple networks) and not a toy.
For a little insight... Thanks to LNP or line number portability there is now an MIN/MDN combination within the HLR (Home Location Registry). The MDN is your Mobile Dialable Number but you also have a MIN which is the Mobile Identification Number (or Routing Number). Some of you AT&T customers may have seen on your TDMA phones you manually programmed a number into your phone that was not your wireless number. This is what allows the porting. People dial your "phone #" which goes to the company who owns your number range (from 0000-9999), who have that number cross referenced with the your current carrier. They then send your call to the carrier your are currently with and your carrier then address' your phone by an assigned routing number (and it is a number in a range they currently own!).
Example: You are with Sprint from 555-0000 and move to AT&T. Your phone is programmed with your ROUTING# 555-1234. You can place calls, but not receive them. Your old phone is still fully functional, so you can RECEIVE/PLACE calls there). AT&T initiates a port request to Sprint. They send Sprint a request with your Name/Addr/Cell#/Acct#/. Sprint setups the link in their systems to Switch/Forward your calls to AT&T. Once the link on Sprints end is completed that allows INCOMING calls to move from Sprint to AT&T and through their switches and to your cell phone via a cross reference to your assigned routing#. Your Sprint account is also closed at this point and your old phone stops working. But ALL your incoming calls go to the carrier who owns your number, and is then sent to your current carrier. This is transparent with GSM as all programming is done Over the Air.
If you have a routing number in your phone, and you call it; you will get someone else as routing numbers are actual phone numbers, but are internal only. All numbers are now used twice. Once as a link from phone to network (routing#, internal, dynamic), and once as a link between network and the world (dialable#, external, static). With the way this system works, they all started with your MIN==MDN, but when you change carriers and as more and more inter/intra-company ports are setup, your routing# will be given to someone else, and will most likely never be a match to your dialable# again.
Your phone# only goes as far as the company who owns it.
Just my 0.02. Jiggs
One multi-band phone (that is TDMA/GSM capable) actually requires a special SIM card for the dual functionality. This SIM module contains the EEPROM equivalent for the TDMA programming of the phone separate from the GSM side of the SIM. This is the Sony T26U (it also utilizes Analog towers too). This a true GSM phone with a TDMA overlay. The Siemans S46 has a built in ROM and uses a SIM, this is a TDMA phone with a GSM overlay.
But all GSM phones require a SIM card, this is not only a spec for the GSM network, but if a GSM phone (assuming multi-band, ie. Siemans S46) is running without a SIM, it would only run in TDMA mode, and if not a multi-band, it would not complete its "power up" to an operational state; it would error and demand a SIM to be entered. The Sony T62U will not function without a SIM.
Most GSM phones are NOT multi-band. They would therefor require a SIM. Multi-band phones generally don't come with the "eye candy" that other phones do (ie. Cam, Colour, Blue Tooth). These are more for people who need a phone to be a phone all the time (best coverage over multiple networks) and not a toy.
For a little insight... Thanks to LNP or line number portability there is now an MIN/MDN combination within the HLR (Home Location Registry). The MDN is your Mobile Dialable Number but you also have a MIN which is the Mobile Identification Number (or Routing Number). Some of you AT&T customers may have seen on your TDMA phones you manually programmed a number into your phone that was not your wireless number. This is what allows the porting. People dial your "phone #" which goes to the company who owns your number range (from 0000-9999), who have that number cross referenced with the your current carrier. They then send your call to the carrier your are currently with and your carrier then address' your phone by an assigned routing number (and it is a number in a range they currently own!).
Example: You are with Sprint from 555-0000 and move to AT&T. Your phone is programmed with your ROUTING# 555-1234. You can place calls, but not receive them. Your old phone is still fully functional, so you can RECEIVE/PLACE calls there). AT&T initiates a port request to Sprint. They send Sprint a request with your Name/Addr/Cell#/Acct#/. Sprint setups the link in their systems to Switch/Forward your calls to AT&T. Once the link on Sprints end is completed that allows INCOMING calls to move from Sprint to AT&T and through their switches and to your cell phone via a cross reference to your assigned routing#. Your Sprint account is also closed at this point and your old phone stops working. But ALL your incoming calls go to the carrier who owns your number, and is then sent to your current carrier. This is transparent with GSM as all programming is done Over the Air.
If you have a routing number in your phone, and you call it; you will get someone else as routing numbers are actual phone numbers, but are internal only. All numbers are now used twice. Once as a link from phone to network (routing#, internal, dynamic), and once as a link between network and the world (dialable#, external, static). With the way this system works, they all started with your MIN==MDN, but when you change carriers and as more and more inter/intra-company ports are setup, your routing# will be given to someone else, and will most likely never be a match to your dialable# again.
Your phone# only goes as far as the company who owns it.
Just my 0.02. Jiggs
