|To get the IMEI on any GSM phone, enter *#06#
To enable caller id, enter *#30#[SEND] To enable call-blocking, enter *#31#[SEND] Note that the two above options are not yet available in most areas.
To enable display of cell-site names, [MENU] 4 9 1
To find the date code of the firmware, enter *#3283# (* # D A T E *). The last two digits are the year. If the year is 95, then the first two digits are the month. For 96 the first two digits are the week of the year.
To find the software version on the 2110e / 2110i, enter *#170602112302# On newer phones, the code has been changed to *#682371158412125#
The phone should display something similar to this:
V 5.31 software version 06-01-96 date manufactured NHE-4 model GE8 = 9000?
Supposedly, versions prior to 5.48 had problems, and would reset themselves in the middle of a call.
pinouts for the accessory connector
You may want to check out the Nokia 2110 FAQ