HiLo-NC has been released by SAGEM company, France, that claims that a smallest GSM module in the world with highest reliablility. This project aims to develop a simple GSM terminal by means of such this module. Design concept is to reduce components count but still giving performance as describes in related application note. Regarding to datasheet and application note are prohibited by SAGEM thus reader can give this design idea to your product as well.

HiLo-NC specifications

1) SMT mount type, 24x24x2.6 mm , ~3g weight.

2) Operation temperature rage -40~+85 degree celcius.

3) Power supply range 3.2~4.5V, 3.7V norminal.

4) Current consumption in standby mode < 1.5mA.

5) Quad band support, EGSM850, GSM900, PCS1800 and PCS1900.

6) Output power, 2W for 850 and 900MHz, 1W for 1800 and 1900 MHz.

7) GPRS multi slot class 10 (3+2 or 4+1), download speed up to 85.6 kbps and upload speed is about 42.8 kbps. Coding cheme support is CS1 to CS4.

8) Mobile station class B, can not simultaneous transmit voice and data.

9) One UART interface, full hardware or software flowcontrol. Speed up to 115200 baud.

10) AT commands set relies on GSM 07.05, GSM 07.07, GSM 07.10 and SAGEM propritary commands.

11) Multiplexing support according to GSM 07.10.

12) CSD and FAX data speed is 9600 bprs. ( Actual speed over GSM air interface, No compression nor multislot support )

13) Rich of tcp/ip protocol stack supports TCP or UDP both client or server mode, FTP client or server, SMTP, POP3. Up to 8 simultaneous connections.

14) General purpose I/O 5 channel, 1 Analog to digital converter.

15) Reset pin for unexpected situation causes module gets hang over.

16)  Voice codec support HR, EFR, FR and AMR.

17) Analog audio interface with echo cancellation and noise reduction.

18) Support all GSM service such as Phonebook, CLIP,CLIR, COLP, COLR, Call waiting, call hold, conference call, call forwarding, call barring, FSN, USSD, Sim tool kit, AoC, SMS,CB, Cell ID, MMS.

19) Support SIM 3V or 1.8V.

 HiLo-NC pin out

Basic UART connection

Schematic diagram

Schematic

DC power supply is connected to P3, D2 blocking reverse polarity which may damage U2. C12,C14,C15 are comprised in order to prevent out side noise or spike. U2 regulate power supply voltage to 3.6V by evaluate reference voltage provided by R6 and R7. C13 acts as energy storage during GSM transmiting there might have 2A trancient peak current. Once SW1 is pressed as long as 3~5 second the GSM module shall start up and provides  PWRON at pin 4. This signal is used by Q1 for power on indicating by D4.

SIM card is now accessed by GSM module. C11, C16, C17, C18, C19 are used for EMI reduction. D3 is normally used for ESD protection which might damage SIM card at all.  GSM module communicates with application through RS232 interface. There is MAX3232 for convert RS232 standard level to 2.8V TTL level. R1, R2, R3, R4 are placed for reduce feed-through current effect by reduce large current which caused by difference voltage level between 2.8V and 3.6V (Ipass = (3.6 - 2.8)/180 = 4.4mA, must less than maximum absolute rating (15mA).

GSM antenna is connected to P4. Assume that antenna has 50 Ohm impedance so no matching network needed. JP1 is automatic start jumper, if you prefer to start the module automatically after power input.

Audio signal is connected through P2 both speaker phone and microphone. It can directly drive 32 Ohm speaker but if you need lounder voice the additional amplifier might be used.

Assembly and test

SAGEM-HiLo/NC AT Commands refference

SAGEM-HiLo/NC Datasheet