Polycom ViewStation EX4000 - Manual (Page 49)

Chapter 2 - Technical Information
© Polycom, Inc. 39
State Machine
The V.35/RS-449/RS-530 state machine controls how the
V.35/RS-449/RS-530 interface signals handshake with the network
interface equipment while the call is being established. The
following tables describe the machine states.
Table 2-22. Dial-Out State Machine
State
ViewStation or
VS4000 Signals
Network Signals
1 Initial State:
DTR = 0
a
RTS = 0 b
CRQ = 0
USER INITIATES
CALL
Initial State:
RI = 0
DLO = 0
ACR = 0
DSR = 0
2 DTR = 1 a
3 Wait 10 ms
4 CRQ = 1
5 PND = 1
6 Set Digit
(NB1,NB2,NB3,NB4)
7 DPR = 1
8 PND = 0
9 DPR = 0
10 If not last digit, go to
state 4; else continue
11 Call connects on
network
12 DSR = 1 AND/OR
DCD = 1
(AND/OR DSR = 1
c
13 RTS = 1 b
14 DATA FLOW STARTS DATA FLOW STARTS
User Hang-up Far end hang-up