Chapter 5 - Error Correction, Data Compression, and Speed Conversion
5.7
Flow Control
Flow control refers to the techniques used by computer devices to stop and restart the flow of data from each other. Flow control is necessary so that a device does not receive more data than it can handle. In the case of the MT2834MR6, there is a need for flow control in both directions. Flow control for data passing from your computer to the modem is called modem-initiated flow control, and flow control for data passing from the modem to your computer is called computer/terminal-initiated pacing (see Figure 5-1).
The MT2834MR6 supports both hardware and software modem-initiated flow control and computer/terminalinitiated pacing. It also supports Hewlett Packard ENQ/ACK pacing. The MT2834MR6 can allow hardware and software pacing to be passed through the modem to the other end of the link so that your computer or terminal can control data start/stop activity through your modem. This is called “XON/XOFF pass-through".
To put it simply, flow control is something the modem does to the computer, while pacing is something the computer does to the modem.
Figure 5-1. Flow control and pacing
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