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! d i g i t a l !   I N T E R O F F I C E  M E M O R A N D U M
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				       Date: 19-February-82
				       From: TSG/NCSS
				       Loc:  MR1-2/H22
				       Ext:  HOTLINE  5911
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Subj:	Bell 212A Strapping Options
.subtitle Subj:	Bell 212A Strapping Options
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.s
There are many customer choices for strapping options on the
BELL 212A modem.  Included here is a list of the factory-installed
strapping options which are the suggested options for connecting the modems
to RSX20F terminal lines.
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	THE STRAPPING OPTIONS ARE AS FOLLOWS
.S
.lit
	SWITCH PACK 1                                                      
                                                            
TIP RING MAKE BUSY		OUT	 S1	0

NOT USED			OUT	 S2	0

CC INDICATION
FOR ANALOG LOOP			ON	 S3	X


	SWITCH PACK 2

SPEED CONTROL
HS BUTTON			CLOSE	 S1	X
				OPEN	 S9	0

INTERFACE CONTROL
MB/AL-ON LEAD			OUT	 S2	X

TRANSMITTER
  TIMING			INT	 S3	0
  					 S4	0

1200BPS OPERATION
  ASYNC/start/stop		OPEN	 S5	0

CHAR LENGTH(10 bit)
USE WITH start/stop		CLOSED	 S6	X

RCVR RESPONDS
TO DIGITAL LOOP			IN	 S7	0

INTERFACE CONTROL
  RDL LEAD			OUT	 S8	0



		SWITCH PACK 3

LOSS OF CARRIER
  DISCONNECT			IN 	 S1	X

RCV SPACE
  DISCONNECT			IN	 S2	X

CB AND CF
INDICATIONS			COM	 S3	X

SEND SPACE
DISCONNECT			IN	 S4	X

AUTOMATIC
ANSWER				IN	 S5	0

ANSWER MODE
INDICATION			OFF	 S6	0

SPEED MODE			DUAL	 S7	0

INTERFACE SPEED
INDICATION			OUT	 S8	0



		SWITCH PACK 5

1200BPS
OPERATION
ASYNC/start/stop		OPEN	S1	0
				OPEN	S2	0

.end lit
The 0 or X following the switch name is the BELL convention used
to describe whether the switch is open or closed.  A 0 is switch open
and an X is switch closed.  
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Many of the switches may be in either position with no effect on the operation
of the modem with RSX20F.  
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The telephone company is responsible for changing the switches on the
logic module inside the modem.  However the following is a representation
of how the switch packs (toggle type) should look when set up as described
above.  Looking at the switch pack so that the numbers of the switches are
right side up each switch may take two positions.  In each position of a 
switch a bar is visible and will appear at the top or bottom of the switch
depending on the position of the switch.  The bar is represented by a ~
.lit
in the illustration.  The ~ will either be above the switch ~
							    S

or below the switch S
		    ~   to show how the switch is to be toggled.
      |-----------|
      |	       ~  |
      |  S  S  S  |
      |  ~  ~     |  
      |  1  2  3  |
      |-----------|

	SWITCH  1




      |----------------------------|
      |	 ~  ~   	~          |
      |  S  S  S  S  S  S  S  S  S |
      |        ~  ~  ~     ~  ~  ~ |  
      |  1  2  3  4  5  6  7  8  9 |
      |----------------------------|


	SWITCH  2





      |----------------------------|
      |	 ~  ~  ~  ~                |
      |  S  S  S  S  S  S  S  S  S |
      |              ~  ~  ~  ~  ~ |  
      |  1  2  3  4  5  6  7  8  9 |
      |----------------------------|


	SWITCH  3





      |--------|
      |	       |	           
      |  S  S  |
      |  ~  ~  |		             
      |  1  2  |
      |--------|

	SWITCH  5
.END LIT