Nn - Select Negotiate Handshake Option

Command Line Format
AT [cmds] N [suffix] [cmds] <CR>

Suffix Values
0 through 5

Default
N1

Stored by &Wn
yes

Displayed by &V
yes

Description
The N command selects whether the local modem performs a negotiated handshake with a remote modem when the communications speed of the two modems is different. Both symmetrical and asymmetrical handshake procedures can be selected.

The choices for originate mode are as follows.

Orig-A - Handshake only at the communication standard specified by S37 and Bn.

Orig-B - Begin handshake at line speed specified by S37. Fallback to a lower speed is allowed. The modem listens for V.23 tone (1300 Hz) and 300-bits/s Frequency Shift Keying (FSK) carrier if either B15 (V.21) or B16 (Industry Standard 103) is selected. If one of the tones is detected, the originate modem tries to connect to the detected modem type. See the Handshake Procedures section.

The choices for answer mode are as follows:

Ans-A - Handshake only at the communication standard specified by S37 and Bn.

Ans-B - Negotiates in the following sequence of communication standards, starting at the highest speed allowed by the value of S37: V.FC, V.32 bis, V.32, V.22bis, (V.22 or Industry Standard 212), V.21, and Industry Standard 103. The selection of V.22 versus Industry Standard 212 depends on the B command in effect.

Ans-C - Negotiates in the following sequence of communication standards, starting at the highest speed allowed by the value of S37: V.FC, V.32 bis, V.32, V.22bis, (V.22 or Industry Standard 212), V.23, V.21, and Industry Standard 103. The selection of V.22 versus Industry Standard 212 depends on the B command in effect.

Note: Ans-C is the same as Ans-B if V.23 modulation is not available.

The following table depicts the options selected with the Nn commands.

Option     N0          N1         N2          N3          N4          N5          

Orig-A     x                                  x           x                       
               
Orig-B                 x          x                                   x           

Ans-A      x                                                          x           

Ans-B                  x                      x                                   

Ans-C                             x                       x

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