1. Altogether there are 25 keys available for operation when the phone is idle 
2. Operations you may try when the phone is idle:
Menu/Confirm Key: Press this key and you may start programming/setting your favorites. Also it serves as a key for confirming your selection.
Phonebook/Cancel Key: Press this key and you may start using your phonebook.
It can also be used for canceling the selection and return to upper entry of the menu.
Redial Key: automatic redialing
Direction Key: UP, DOWN, LEFT, RIGHT
Confirmation Key: confirming your choice
Return Key: Press this key and the LCD display returns back to its standby status.
Message Key: Press this key and you may start using message functions.
Dispatch/Send Key: Press this key and the dialed numbers will be displayed.
Come to one displayed number and press for the second time if you want to call that number.
You may also press it for faster forwarding after your dial.
Call Info. Key: Press this key and you may enter the call info directory. 
Hands-Free Key: Use to activateoff-hook dialing or to answer, with handset remaining hooked.
 

Technical Specifications:

GSM Frequency: 900/1800 MHz
GSM 900
Transmission: 890-915 MHz
Reception: 935-960 MHz
GSM 1800 
Transmission: 1710-1785 MHz
Reception: 1805-1880 MHz
Carrier Spacing: 200 KHz
GSM Category Four Transceiver: 2 W for GSM 900
                               1 W for GSM 1800
Maximum Frequency Deviation: ±0.1 ppm
Receiving Sensitivity: -105 dBm
Phase Error: < 5°RMS
SIM Card: Mini-SIM Card
Shell Material: Flame-retardant ABS
Working Temperature Range: -20??+40?
Humidity Range: ?95% RH
Standby Current: ?80mA
Audio Distortion: < 3%

Power Supply:

Power Supply: AC 220V (working voltage: from 120 V to 280 V, protected when the power is over 280V,)
DC Voltage: 12V/DC
Current Rating; 2A
Battery: Standby time: 20 hours
         Back-up talk time: 2 hours

Function Overview:

From the menu, you may enter the following 6 main entries: Text Message, Phonebook, Call Info, Call Divert, Settings and Tools.
For Text Message, there are Inbox, Outbox, Write, Settings and Voicemail.
For Phonebook, there are Number Search, Add Entry, Total List, Group Settings and Memory Status.
For Call Info, there are Missed (calls), Received (calls), Dialed (calls) and Call Timers.
For Call Divert, there are (diverting) All Calls, (diverting when there is) no answer, (diverting when the phone is) busy,
(diverting when the phone is) not reachable, Status (reference) and Cancel All (for cancellation of all diverts).
For Settings, there are Phone Settings, Call Settings and (settings) for Safety.
For Tools, there are Clock, Date, World Clock, Calculator, Alarm Clock and Schedules.

Lots of other options here www.gsmspeakerphone.com