NEC Property Management System Communication Interface Specification

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Property Management System - Communication Interface Architecture
Table 2-5  Line Control Characteristics
Item Conditions
Control Method Contention method (point to point)
Operating Mode Half duplex (if modems are used, set to full duplex)
Synchronization Synchronous
Data Rate 4800 or 9600 bits/second (bps)
Frame Contents EBCDIC
Error Control Method CRC-16 (X
16 + X15 + X2 + 1)
Bit Transmission Order Priority is given to low order bits
Transmission Intervals At each data...

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The control codes used for the message texts are:
Table 2-6  Control Codes
Control CodeHexadecimal 
Va l u eFunction
SYN 32 Synchronization code.
STX 02 Indicates the start of a block.
ETX 03 Indicates the end of a block.
ENQ 2D Used as the start sequence code. It indicates a reception 
request to the other side and a request to answer an infor-
mation block just sent.
EOT 04 Indicates the end of transmission...

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Transmission 
ProtocolThe messages sent between the NEAX and the PMS must have header and trailing 
sections as defined in the following format:
Figure 2-5   Base Message Format
The elements of the message is as follows:
PAD-L -- The leading pad character. (One byte - 55H.)
SYN -- Synchronization character. At least three of these should be transmitted. 
(One byte each - 32H.)
STX -- Start of text block....

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The message format breaks down as follows:
STX -- Start of text block. (One byte - 02H.)
SA -- System Address. (One byte - ‘1’ [31H].)
UA -- I/O Unit Address. (One byte - ‘!’ [21H].)
EI -- Entry Index. (One byte - ‘L’ [4CH].)
FTC -- Feature Code. (See below.) A list is provided in Appendix C, “Feature 
Codes”.
MSC -- Message Counter. This represents the length of the message. The count 
of characters...

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Transmission 
Sequence
Table 2-7  Data Transmission Sequence (1 of 2)
Status ENQ STXETX,
CRCACK0/
ACK1NAK
Neutral (A) a: ACK0 -> 
(B)
b: NAK -> 
(A)
c: ENQ -> 
(D)
Waiting for 
STX (B)(ACK last 
received) -> 
(B)-> (C)
Waiting for 
ETX, CRC 
(C)f: NAK -> 
(B)
g: EOT -> 
(A)h: ACK0/1
i: NAK
c: RVI
j: EOT
-> (A)
Waiting for 
ACK after 
start 
sequence 
(D)f: ENQ -> 
(D)
g: EOT -> 
(A)d: ENQ -> 
(D)
e: EOT ->...

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Notes:
a: Preparation for reception complete.
b: Reception impossible.
c: Requests for preparation for reception (the PMS should not request this).
d: Transmitted up to 21 times.
e: Aborted at 22nd time.
f: Transmitted up to 7 times.
g: Aborted on the 8th time.
h: Message is received normally and preparation for next reception is complete.
i: Error found in message.
j: Interruption.
k: Information...

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Timers and 
CountersRetransmission Counts
Timer Values
Table 2-9  Retransmission Counts
Meaning Count
The number of retransmissions of the start sequence when there is no 
answer after transmitting the start sequence.7
The number of retransmissions of the start sequence when NAK is 
received after transmitting the start sequence.7
The number of transmitting ENQs when WACK is received after the 
transmission...

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Cabling 
ConsiderationsWhen the PMS is connected to the NEAX through a modem, the cables should just 
be “straight through” cables. There should be no crossing.
When the PMS is directly connected to the NEAX, use the following pin 
assignments:
Figure 2-7   Direct Connection Pin Assignments
1FG
SD
RD
RS
CS
DR
SG
CD
ST
2
RT
ER
ST
1
2
3
4
5
6
7
8
15
17
20
24FG
SD
RD
RS
CS
DR
SG
CD
ST
2
RT
ER
ST
1
1
2
3
4
5
6
7...

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Property Management System - Communication Interface Message Descriptions
Chapter 3 Message Descriptions
There are several message groups:
Data Link Maintenance Messages
Maid Status
Message Waiting Lamp Control
Restriction Control
Check In/Check Out (Model 60)
Check In/Check Out (Model 90)
Wake Up/Group Announcement
Room Move/Swap/Copy (Model 60)
Room Data Change
Extension Report
Room Recovery (Model 60)
Room Recovery (Model 90)
Direct Data Entry (Model 90)...

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Recovery Start Report -- After receiving the Nop Test Recover Answer 
message, the PMS must download NEAX database information (see “Room 
Recovery (Model 60)” on page 27 and “Room Recovery (Model 90)” on page 
28). This message notifies the NEAX of the incoming download.
Recovery End Report -- Reports to the NEAX that the PMS database download 
is complete.
Data Link Release Request -- Used by...