3Com 10014299 manual POS Network Access, Advantages of POS network access are as follows

96CHAPTER 7: POS TERMINAL ACCESS SERVICE

Figure 40 Dial-up access when the POS access router is located at the commercial client side

POS terminal			PSTN/ISDN
	PSTN/
POS terminal	PBX	FCM	X.25/FR/DDN

Router Router UNIX FEP

POS terminal

Due to the way POS access service usually operates, that is, low speed, high frequency and small traffic, it is rather sensitive to the dial-up connection time and requires the interface board for fast dial-up function. However, the present common PC modem cannot meet the response time requirements of 10 to 20 seconds. At present, most POS equipment manufacturers use the special modem chip that supports fast connection to implement the function. The FCM card of the 3Com Router series is a fast handshaking modem specially designed for POS dial-up access service.

POS Network Access

In the POS network access mode, the router providing POS access service is located at the commercial client end and helps all the POS terminals access the 3Com Router series. The router located at the FEP side can be any router and communicates with the 3Com Router series through X.25, FR, DDN, ISDN or modem.

The following figure shows the networking of typical POS network access.

Figure 41 Access mode when the POS access router located at the commercial client end

POS1	RS-232	Long line
	POS	driv e	Serial
RS-485		PSTN, ISDN	port
		X.25,FR,DDN	Ethernet
POS2		Router	Router interface
	RS-232		UNIX FEP
	POS
	concentrator

In the POS network access mode, 3Com Router series can be connected to the

POS terminal in the following two ways:

■Directly connect the POS RS-232 connector with the asynchronous interface (including the asynchronous mode of the synchronous/asynchronous interface) of the 3Com Router series. If the distance between them exceeds 15 meters, it will be necessary to install a long-line-driver at each end of the connection line. The valid connection distance of a pair of passive long-line-drivers is about 1200 meters.

■Set up an RS-485 network with the POS terminal device and POS concentrator, then connect the RS-232 connector of the POS concentrator with the asynchronous interface of the 3Com Router series. The 3Com Router series communicate on the egress port in the same way as the first connection method. Access in this way can save the router interface source greatly.

The advantages of POS network access are as follows: