Справочник Пользователя для NEC NDA-30115-001
Page 10
NDA-30115 Revision 1.0
Architecture
Property Management System - Communication Interface
Timers
The following timers are used to maintain data transmission:
Sender Timer
Upon sending a start sequence, message text or query, this timer begins counting
and stops counting upon receiving a valid answer control code. This timer is set to
one (1) second. If a timeout occurs after the transmission of a start sequence, a start
sequence will be resent up to 15 times. If a timeout occurs during the transmission
of a message text or query, a query is sent up to 32 times.
and stops counting upon receiving a valid answer control code. This timer is set to
one (1) second. If a timeout occurs after the transmission of a start sequence, a start
sequence will be resent up to 15 times. If a timeout occurs during the transmission
of a message text or query, a query is sent up to 32 times.
Receiver Timer
Upon transmission of a positive acknowledgment for a start sequence or a message
text, this timer begins counting and stops counting upon receiving a message text
or an end code. This timer is set to 35 seconds. If a timeout occurs, the sender loses
send rights.
text, this timer begins counting and stops counting upon receiving a message text
or an end code. This timer is set to 35 seconds. If a timeout occurs, the sender loses
send rights.
Cabling
Considerations
Considerations
When the PMS is connected to the NEAX through a modem, the cables should just
be “straight through” cables. There should be no crossing.
be “straight through” cables. There should be no crossing.
When the PMS is directly connected to the NEAX, use the following pin
assignments:
assignments:
Figure 2-4 Direct Connection Pin Assignments
Bisynchronous (BSC) Transmission
Line Control
Characteristics
Characteristics
The characteristics of the signals transmitted across the communications link are as
follows:
follows:
1
FG
SD
RD
RS
CS
DR
SG
CD
ER
2
3
4
5
6
7
8
20
FG
SD
RD
RS
CS
DR
SG
CD
ER
1
2
3
4
5
6
7
8
20
Pin No. Signal
Cable
Signal
Pin No.
NEAX
PMS