S82 - Break Selection


Description
This register determines how breaks are transmitted during error-control and ASB calls. The following options are provided.

In-sequence means a break is sent to the distant end after any buffered data, without disrupting the data being transmitted. Incoming data is sent to the local DTE after any buffered data.

Expedited means breaks are sent to the distant end or delivered to the DTE before any buffered data, while maintaining the integrity of the data. An expedited break is delivered to the receiving DTE without regard for flow control.

Destructive means all buffered data is discarded before the break is sent; the buffered data is lost. Destructive implies expedited; the break is sent instead of buffered data. Thus destructive and expedited breaks occur if the value of bit 2 is 1, independent of bit 1. If the receiving DCE is flowed off by its DTE, then an in-sequence break must wait until the flow restraint is released before the DCE can deliver the break to the DTE without regard for the current flow control status. Characters must wait for flow control to be released.

V.42 LAPM allows the sending end to tell the receiving end when a break is timed. The receiving modem delivers breaks that are timed according to the indication from the distant modem.

When using LAPM, timed break durations are in increments of 10 ms. Timed breaks are sent with duration equal to the closest time increment that is not less than the duration received from the DTE.

If a V.42 Alternative Procedure connection is made then the modem only provides untimed breaks; bit 0 is ignored. The procedure does not include timed breaks.

When using ASB, timed breaks are timed according to the procedure described in V.14: breaks that last M to 2*M + 3 bits (M is the length of a character) are sent with duration 2*M + 3 bits. Longer breaks are sent with their true duration. Less than M spacing bits from the DTE are ignored, not treated as breaks. The duration of untimed breaks is the larger of 180 ms or 2M + 3 bits .

When using ASB, incoming breaks are delivered to the DTE in sequence, after any other buffered data.

Note: National parameter 72 determines how breaks are handled when X.25 protocol is in use and V.14 specifies how breaks are handled when that recommendation is in use.

Type
bit-mapped; Default Value: 1

Stored by &Wn
yes

Displayed by &V
no 

Bit Map 



Bit        Description                                

7          0 = untimed,                               
			 1 = timed (for compatibility)              

6          reserved                                   

5          reserved                                   

4          reserved                                   

3          reserved                                   

2          0 = not destructive,                       
			 1 = destructive                            

1          0 = in sequence,                           
			 1 = expedited                              

0          0 = untimed,                               
			 1 = timed                                  

                                                      

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