Filter
Top Products
Manual Fusion Intelpage IP
© CommtechWireless Page 43
4 TECHNICAL INFORMATION
4.1 Binary AND Masking
The four numerical values of an IP address range between 0-255. These are all decimal
numbers (base 10). Most scientific calculators (including the one found in Windows)
allow conversion to and from decimal to binary (base 2).
After conversion, the range in binary is 0000 0000 to 1111 1111. The decimal values of
the 8 bits from right to left are: 1, 2, 4, 8, 16, 32, 64, 128. These numbers are actually
2^0, 2^1, 2^2, 2^3 etc. The value of a binary number in decimal can be calculated by
summing the decimal values of the bits that are ‘1’. An IP address of say 192.168.0.52
would be 1100 0000 1010 1000 0000 0000 0011 0100 in binary.
Masking involves a binary AND of two numbers, in this case, a received IP and the
mask. Any binary value AND with a ‘0’ becomes ‘0’. Any binary value AND with a ‘1’
remains the same.
Consider the following example:
Received IP 1100 0000 1010 1000 0000 0000 0111 1011
(192.168.0.123)
Mask 1111 1111 1111 1111 1111 1111 0000 0000
(255.255.255.0)
AND Result 1100 0000 1010 1000 0000 0000 0000 0000
(192.168.0.0)
From the example, we can see that regardless of the last (right most) 8 bits, the Mask will
always set them all to ‘0’. So even if the received IP was say 192.168.0.234, the AND
result will still be 192.168.0.0.
Therefore, if 192.168.0.0 is placed in the access list with the mask 255.255.255.0, all the
received IP addresses from 192.168.0.0 to 192.168.0.254 will be accepted (a 255 on the
end means broadcast).
4.2 Communications
Both the Ethernet and serial connections allow a cable to transfer data between two
systems in close proximity. Intelpage IP 5 can receive TAP, COMP, WAVEWARE,
SCOPE, TNPP and SMTP messages as IP or serial (excluding SMTP) data from other
systems.
4.2.1 Ethernet Connection
The RJ45 port on Intelpage IP 5 is an Ethernet port like any other that may be found on a
PC or network device. The Intelpage IP 5 supports 10Mbps Ethernet connections.
If the Intelpage IP 5 is to be connected to a PC network (i.e.. into a switch or hub), then a
straight-through cable should be used. A straight through Ethernet cable is included in the
package. (red cable)