regards

On Thu, May 19, 2011 at 9:04 PM, Gianni Tedesco <gianni@scaramanga.co.uk> wrote:

On Fri, 2011-05-13 at 15:00 +0430, Mohammad Hosein wrote:

> you could use most GSM test systems for such purpose . on ebay you
> might find very cheap ones
> regards

I managed to track down a Racal 6103. It should arrive in next couple of
days.

As a followup question then, I guess that these are intended for wired
rf connection or at least they transmit at very low power, and tell the
phone to do the same.

However, one would feel a lot better using a channel unused by other
cells in my location. I've been using cell_log to put together a list of
active ARFCN's that my handset receives broadcasts from. Script for
parsing cell_log logs is attached.

Am I to conclude that if cell_log hasn't dumped:

[sysinfo]
arfcn 99

for example, after running for a reasonably long period of time (say
24hrs) that operating test equipment on channel 99 should be safe?

Gianni

--

#!/usr/bin/python

def getline(f):
while True:
l = f.readline()
if not l:
raise StopIteration
l = l.rstrip('\r\n')
if not l:
continue
yield l
def bsic(v):
(a,b) = v.split(',')
return (int(a),int(b))

def hexdump(v):
ret = bytearray()
for x in v.split():
ret.append(int(x, 16))
return ret

class Parser:
pass

class Power(Parser):
def line(self, s):
return

class mcc:
tbl = {0x234: 'UK and Northern Ireland'}
def __init__(self, num):
x = ((num & 0xf00) >> 8,
(num & 0xf000) >> 12,
(num & 0xf))
self.val = (x[0] << 8) | x[1] << 4 | x[2]
def __int__(self):
return self.val
def __str__(self):
return self.tbl.get(self.val, '%.3x'%self.val)

class mnc:
tbl = {0x15: 'Vodafone',
0x30: 'T-Mobile',
0x10: 'O2',
0x33: 'Orange',
}
def __init__(self, num):
x = ((num & 0xf0) >> 4,
(num & 0xf))
self.val = (x[1] << 4) | x[0]
def __int__(self):
return self.val
def __str__(self):
return self.tbl.get(self.val, '%.2x'%self.val)

class SystemInfo:
pass

class SystemInfo3(SystemInfo):
def __init__(self, b):
if isinstance(b, str):
b = hexdump(b)
assert(b[0] > 9) # len
assert(b[1] == 0x06) # discr
assert(b[2] == 0x1b) # sysinfo3
self.cell = (b[3] << 8) | b[4]
self.mcc = mcc((b[5] << 8) | b[6])
self.mnc = mnc(b[7])
self.lac = (b[8] << 8) | b[9]
def __str__(self):
return 'Cell(%s, %s)'%(self.mcc,self.mnc)

class SystemInfo4(SystemInfo):
def __init__(self, b):
if isinstance(b, str):
b = hexdump(b)
assert(b[0] > 7) # len
assert(b[1] == 0x06) # discr
assert(b[2] == 0x1c) # sysinfo4
self.cell = None
self.mcc = mcc((b[3] << 8) | b[4])
self.mnc = mnc(b[5])
self.lac = (b[6] << 8) | b[7]
def __str__(self):
return 'Cell(%s, %s)'%(self.mcc,self.mnc)

class Sysinfo(Parser):
_keys = {'arfcn':int,
'time':int,
'rxlev':int,
'bsic':bsic,
'si1':hexdump,
'si2':hexdump,
'si2bis':hexdump,
'si2ter':hexdump,
'si3':SystemInfo3,
'si4':SystemInfo4,
'ta':int}
def line(self, s):
(k,v) = s.split(None, 1)
if self._keys.has_key(k):
setattr(self, k, self._keys[k](v))
else:
print k, v
return

class RFMap:
arfcns = {}
cells = {}
def commit(self, obj):
if isinstance(obj, Sysinfo):
self.arfcns.setdefault(obj.arfcn, {})
self.arfcns[obj.arfcn][str(obj.si3.mnc)] = None
self.arfcns[obj.arfcn][str(obj.si4.mnc)] = None

self.cells.setdefault(obj.si3.cell, {})
self.cells[obj.si3.cell][str(obj.si3.mnc)] = None
elif isinstance(obj, Power):
return
assert(isinstance(obj, Parser))

def rf_map(f):
smap = {'[power]':Power, '[sysinfo]':Sysinfo}
obj = None
m = RFMap()

for x in getline(f):
if x[0] == '[':
if obj is not None:
m.commit(obj)
obj = smap[x]()
continue
if obj is None:
raise ValueError, 'Bad state'
obj.line(x)

if obj is not None:
m.commit(obj)

print 'Active ARFCNs:'
x = m.arfcns.keys()
x.sort()
for i in x:
print ' %4d:'%i, ','.join(m.arfcns[i])
print

print 'Active Cells:'
x = m.cells.keys()
x.sort()
for i in x:
print ' 0x%.4x'%i, ','.join(m.cells[i])
print

def main(argv):
if len(argv) > 1:
infile = open(argv[1])
else:
from sys import stdin
infile = stdin

rf_map(infile)
return 0

if __name__ == '__main__':
from sys import argv
raise SystemExit, main(argv)