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m S on y-E ric ss o n )






F ig u res 3 .a , 3 .b a n d 3 .c s h o w th e d if f e re n t v ie w s o f t h e G SM m odem G M 28
( F ro m t h e H ard w are M anua l o f G M 28 M odem )

T he G lo b al S yste m f o r M ob ile C om munic a tio n s ( G SM ) i s t h e m ost p opu la r s ta n dard
f o r m obile p hones in th e w orld . It is th e E uro pean sta n dard fo r d ig ita l c ellu la r se rv ic e th at
i n clu des e n han ce d f e atu re s. I t i s b ase d o n T D M A t e ch nolo gy a n d i s u se d o n 8 50/1 900 M Hz.
W e are u sin g t
h e G M 28 , a G SM m odem fro m S on y-E ric ss o n. T his is a p ow erf u l
G SM /G PR S T erm in al w ith co m pact an d se lf -c o nta in ed unit. T his has sta n dard co nnecto r
i n te rfa ces a n d h as a n i n te g ra l S IM c ard r e ad er. T he m odem h as a R J9 c o nnec to r t h ro ugh w hic h
a s p ea k er a n d m ic ro phon e c an b e c o nnec te d a ll o w in g a u dio c alls b ein g e sta b lis h ed , b ut th is
f e a tu re is not util iz e d in th is pro je ct as only data tr a n sfe r is nee d ed . F ollo w in g are fe w
t e ch nic a l d eta ils o f t h e m odem .

I n te rfa ces:
· Data : R S232 9 –w ay ( V .2 8)
· Pow er a n d E xte n d ed I /O s: 5 – 3 2V DC ( R