Technical Reference for ZyXEL omni.net series

 

Standard

 

Speed (bps)

 

 

Notes

V.21

 

300

 

 

 

 

V.22

 

1200

 

 

 

 

V.22 bis

 

2400 or 1200

 

 

V.32

 

9600 or 4800

 

 

V.32 bis

 

14400, 12000, 7200

 

 

 

V.34

 

33600

– 2400

 

 

V.90

 

56000

– 28000

 

 

Table 55. Modem Standards and Speeds

MNP Protocols

MNP (Microcom Network Protocol) is a set of protocols first introduced by Microcom, Inc., and alter used by many modem manufacturers. It consists of many classes. Class 1 to 4 are for error correction, and class 5 is for data compression. MNP Class 1 and 2 are obsolete. Normally Class 4 is used for error correction and it uses Class 3 internally.

MNP Class 5 is data compression protocol with a maximum efficiency of 2 to 1. MNP-5 is used with MNP-4 for error correction.

Xmodem, Ymodem, and Zmodem

These are file transfer protocols. They do error checking and ensure data integrity of the file transferred. Some variations of these protocols also appear, like Xmodem-1k, Ymodem-G, etc.

The “G” types of protocols do not include error checking. They allow very high throughput rates, but can be safely used only when the modems use MNP4 or V.42 error protocols and there is no speed overrun on the computer’s serial port.

Whenever possible, we recommend the use of Zmodem for added security and high flexibility. Consult your communications program manual for more information on transfer protocols.

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