Reg Status

After selecting a cell, the phone connects to it. Then just like having to enter a username and password before doing anything on a website, the phone must be 'logged in' before being able to call, text, or use data. Securely 'logging in' is done automatically, credentials are stored in the SIM. There's logging in for calls and texts and all that go along with these, and there's logging in for data and all that goes along with it, and these are considered separate in 2G, as MM and GMM.

NOT_REGISTER

An initial status that will most likely change soon.

REGISTER_HOME

The phone is currently registered('logged in') and will most likely be able to make and receive calls, and send and receive texts.

REGISTER_ROAM

The phone is currently 'logged in' over a carrier not meant for the SIM. For example, while traveling to another country, the home SIM may continue to work if the SIM's carrier and a foreign carrier are connected in a certain way. Services are then normally at a much higher price.

LIMITED

MM limited service. If the version is new enough, check the MM REJECT for a cause. If the phone is configured to be data-only and data is working normally, it remains LIMITED.

SYSTEM_LOSS

No 2G signal or the phone is unable to understand the 2G signal, i.e. loss of the 2G system.

UNKNOWN

Unknown status.

MCC and MNC

Mobile Country Code and Mobile Network Code, also known as the PLMN ID, Public Land Mobile Network Identity. This is what's broadcasted by the tower for the cell the phone camped on.

MCC

The Mobile Country Code is the country broadcasted by the tower, represented as a 3-digit code.

MNC

The Mobile Network Code is a 2 or 3 digit code that identifies the carrier (mobile network operator) in the country, broadcasted by the tower.

RAT

RAT: GSM(2G), so the Radio Access Technology is GSM(2G).

Band

It is a range of frequencies. In 2G, 850/900 and 1800/1900 also differ in transmit power.

2.4GHz and 5GHz in Wi-Fi are like two bands in cellular:

Devices may support 2.4GHz but lack support for 5GHz.
Wi-Fi routers may support/use both, 2.4GHz only, or 5GHz only.
Inside the band, there are several Wi-Fi channels that can be chosen. In cellular, the band and channels (arfcns) used on towers depends on the licenses granted to the mobile network operator. The mobile network operator cannot freely choose a band and a channel.
The signal propagates differently, e.g. certain bands can have a better range.

Each 2G channel is always 0.2MHz wide.

Band:PGSM900

Subset of what is now Band 8. It has channel numbers close to 1.

Band:EGSM900

The part that's outside the PGSM900 subset.

Band:GSM850

Also known as Band 5.

Band:DCS1800

Also known as Band 3.

Band:PCS1900

Also known as Band 2.

BCCH arfcn

The BCCH arfcn is the channel number of the broadcast channel. The broadcast channel is for broadcasts, such as settings mobile phones are to use for 2G. It is not the channel number of the traffic channel.

Wi-Fi has bands (e.g. 2.4GHz) and channels in those bands (e.g. Channel 5), in 2G there are bands and channels inside those bands too.

On 3G and newer, the band can be derived from the channel number. On 2G, it is only possible to do so to an extent, there are regional differences of what a channel number means.

Each channel is +0.2MHz off the previous channel, unless the end is reached. Each channel is 0.2MHz wide.

A carrier can only use a channel if it has a license to use it. For example, a carrier may own 5MHz in a single band, meaning that there are then 25 channel numbers available to it, 5MHz / 0.2MHz = 25.

Rx Lvl

Receive Level is the signal strength. Because 2G's channels are small and many, interference occurs less often, so the signal strength can be a good indicator of how good it is.

A higher Rx Lvl (closer to -47) is generally better. There are diminishing returns.

Displaying a value higher than -47 at Rx Lvl is not supported.

TCH Rx Lvl

Receive Level (signal strength) of the traffic channel. The TCH Rx Lvl is available during a call, during texting, or during signaling, else it's --.

A higher TCH Rx Lvl (closer to -47) is generally better. There are diminishing returns.

Rx Q

Receive Quality is a representation of an error rate. 7 means the most errors, 0 means the fewest. The Rx Q is available during a call, during texting, or during signaling, else it's --.

NOM

Network Operation Mode. This affects how the phone is notified when there is something it should receive.

There's a part of 2G meant for notifying of incoming calls and another part for notifying of data. How these are actually used depends on the Network Operation Mode.

RAC

Routing Area Code.

What it is meant to be used for is that if the phone has data to receive, all towers in the RAC notify the phone so that it can notify the carrier of which cell it is currently in and begin to receive data in it. If the phone moves to another RAC, it notifies the carrier so that the carrier knows where to find it.

CellId

Cell Identity. Cell is an area of coverage from a part of a cell tower.

Though it is displayed in the software as CellId : 0x12341, it's actually not hexadecimal, it's decimal.

Generally, if the CellId is 12341, then the tower is 1234 and the part-of-tower is 1.

Part-of-tower: Each common cell tower has 3 sides, in each side, there may be one or more bands. e.g. one band may be 1,2,3 and the other band may be 4,5,6.

LAC

Location Area Code.

What it is meant to be used for is that if the phone has an inbound call/text, all towers in the LAC notify the phone so that it can notify the carrier of which cell it is currently in and begin to receive the call in it. If the phone moves to another LAC, it notifies the carrier so that the carrier knows where to find it.

Timing Advance

The Timing Advance updates in real-time while the phone is communicating with the tower. It is reliable while in a call, not reliable while using data.

What 2G does is adjust itself for transmissions that arrive late. The Timing Advance increments +1 per each 550 meters the signal has to travel to the tower. If the signal is echoed, the distance obtained from the Timing Advance may be skewed a bit. It's okay if it's slightly wrong.

Tx_Pwr_Lvl

Transmit Power Level. The band determines the maximum transmit power level.

Freq Hopping Status

The phone may hop along a list of frequencies if enabled by the carrier, in an attempt to limit the effects of interference. If this feature is not used, the carrier can't simply switch it on, planning is required. The BCCH arfcn can still be changed, even with it off.

Freq Hopping Status: --

Initial state, such as if 2G is not available.

Freq Hopping Status: <OFF>

Not available or the phone is currently not using 2G services for a voice call or similar.

Freq Hopping Status: <ON>

Currently in use.

GMM/MM REJECT

Refer to Cause.

LTE PS/CS REJECT

Refer to Cause.