Programmer’s Guide
ITherm™ POSjet™ BANKjet™
Network Basics
Ethernet Adapter
Apr-04
Rev C
Page 31
10BaseT
10baseT is also sometimes known as twisted pair. A distance of up to 30 meters between the
connected devices is the recommended limit. The TransAct Ethernet adapter is a 10BaseT
device.
TCP/IP Basics, the TCP/IP protocol
TCP/IP Introduction
TCP/IP or Transmission Control Protocol/Internet Protocol is the network protocol used for the
internet and many local area networks.
Each device is given it’s own Internet Protocol address typically referred to as the IP Address. IP
Addresses are assigned either automatically or manually. This IP address is unique to the device
and cannot be used by any other device else inside the local network.
A typical IP address might look something like this: 192.168.1.80
IP Addresses
IP address consist of 4, 8 bit digits. Being an 8 bit value they may have values from 0 to 255.
For convenience the addresses are written as 4 numbers separated by periods. For example
“192.168.1.80”. A local network or Subnet will typically have the first 3 numbers the same.
For example two devices on a local network might have 192.168.1.80 and 192.168.1.81
respectively. The first number in the group IE the 192 can have additional meaning, however,
local networks are typically assigned value of 192.
Subnet Masks
Typically a subnet mask will look like this: 255.255.255.0. Each bit is a subnet mask is used to
determine if the IP address is in the subnet. If a bit is set in the subnet mask the IP. This
effectively defines how many devices can be in the subnet. In this case 255 because the last 8 bit
value is not masked and all possible values will be recognized as being part of the subnet.
Gateway addresses
One feature TCP/IP is that it is routable. That means that you can use a router or gateway to
expand a local network into multiple networks.
The router allows the two networks to talk to each other. If a user wants to pass information from
network A to network B, the router will pass the information back and forth.
The Gateway address is the IP address of the router that is interconnecting the local subnet to the
remainder of the network.
