With all of the latest hullabaloo about cell phones being used as bugging devices, you may be feeling a bit creeped out at the prospect of being monitored without your knowing it. Although some cell phones can be remotely programmed, most modern cell phones would require physical access to your phone to tamper with it. Luckily, when cell phones are transmitting, certain telltale signs can be a dead giveaway that your phone is being monitored.
Determine if you have an unusually low call volume or if you are having sporadic troubles dialling out on your phone. Most phones, when operating as a bugging device, disrupt the transmission path by utilising it in order to spy. Some newer "3G" phones bypass this problem by running super high-speed data, which can enable additional voice channels along with the primary call line.
Pay attention to your battery power and usage---does it seem to be running low more quickly than usual? This may indicate the phone is in use while you are unaware of it.
Check to see if the phone is warm even when you have not been using it. Cell phones heat up when in use, but should not be warm under normal resting conditions.
Test your GSM phone (most phones are GSM in the United States, including T-Mobile and Cingular) by positioning it next to speakers when you are not using it. A short-lived buzzing noise often occurs when phones are near speakers and sometimes even when they are not in use; however, a continuous buzzing noise that lasts longer than several seconds is abnormal.
Notice if your phone stays lit up after you have powered it down or if you have difficulty turning it off---this could indicate a bugging device. Other signs may be the phone periodically lighting up when not in use or odd clicking sounds or other unusual noises while the phone is in use.
You can have the software wiped on your phone by bringing it into your local wireless provider. Commercial bug detectors can detect cameras and listening devices. Conventional GSM (Global System for Mobile Communications) data channels will often block calls while in active transmitting or receiving mode due to its narrow band technology. The digital air interface available in Code Division Multiple Access (CDMA) allows multiple calls overlaid on top of each other across the channel.
The speaker test does not work as well on phones that are non-GSM and instead use CDMA technology. Sprint and Verizon phones use this technology and therefore may be easier to bug than other phone types.