TROUBLESHOOTING GUIDE
Ascom Myco 3 Troubleshooting Tools
The Signal strength field shows the current RSSI. The signal is displayed both in decibels (dBM), as well as
Arbitrary Strength Unit (ASU).
Decibels are expressed as a negative number, like -70 dBm. The closer the number is to 0, the stronger the
signal. For example, -70 dBm is a stronger signal than -90 dBm. A signal beyond -98dBm is not considered
strong enough to work properly.
RSSI Signal Strength
≥ -70 dBm Excellent
-70 dBm to -85dBm Good
-85 dBm to -98 dBm Fair
-98 dBm to -105 dBm Poor
≤ -105 dBm No Signal
The ASU is an integer value proportional to the received signal strength measured by the handset. ASU is
just a representation of the rate at which the handset is able to update its location by connecting to the
towers near it. It basically measures the same thing as dBm, but on a more linear scale.
You can convert ASU to dBm with this formula:
-In GSM networks, ASU maps to RSSI (received signal strength indicator):
dBm = 2 * ASU - 113, ASU in the range of 0..31 and 99 (for not known or not detectable).
-In UMTS networks, ASU maps to RSCP level (received signal code power):
dBm = ASU - 116, ASU in the range of -5..91 and 255 (for not known or not detectable).
A signal of -60dBm is nearly perfect, and -112dBm is call-dropping bad. If you're above about -87 dBm,
Android will report full signal.
5.2 Protocol Analyzer Tools
Capturing the traffic data with a wireless or wired protocol analyzer can be very useful when
troubleshooting a system. Specifically when using WLAN, as capturing traffic in the spot where the
problems arise may provide valuable information about the traffic that is not transferred over to the wired
network, for example, retransmissions or rates. Since the wired side is almost always a switched network,
capturing traffic is not trivial since access to the switches is needed to create a spanned port to get the data
mirrored out to the sniffer. On the other hand, capturing the WLAN which is a broadcast medium is very
convenient. The only equipment needed is a laptop, for physical mobility, and a wireless network card that
the sniffer software supports.
General Practices
• Always try to capture as much data as possible. If filtering options exists try to filter the result after the
capture is saved. Applying a filter to the capture itself may exclude interesting packets and ultimately
render the capture useless.
TD 93297EN / 19 December 2019 / Ver. B 19
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