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== LINK-20 USER'S MANUAL ==

Phone Lines
OR
Direct Connection

Link-20/cComputer Connection

Link-20 connects to a computer in the same way that an additional
terminal would be connected. It responds to commands or requests
for information from the computer in much the same manner that a
data entry cleric would respond to commands and requests at a
terminal. It can be connected to any computer which will support
at least one asynchronous terminal (in addition to the system
Console).

The data rates have been kept low to allow communication over
poor or questionable quality telephone lines. If errors are
encountered, Link-20 signals the computer to re-transmit the data.
This results in very reliable data transmission, with almost no
chance of lost or garbled data.

The remainder of this manual deals with the technical
specifications of the Link-20 interface.

DATA COMMUNICATIONS FORMAT SUMMARY

Transmission Type: Serial, Asynchronous ASCII
Baud Rate: 1200
Number of Data Bits: 8
Number of Start Bits: 1
Number of Stop Sits: 1
Parity: None

LINK-20 USER'S MANUAL

COMMUNICATION SPECIFICATION
LOW LEVEL DRIVE

In order to assure accurate as well as rapid data transfer, the
Spectrum has adopted a communications protocol to handle basic
low-level errors.

This protocol will be used for all fields allowing data errors to
be corrected by the serial port drivers, instead of the higher
level applications program.

The driver will wait on character strings to either receive or
transmit.

In the case of receive, the driver will count the number of
characters it receives, until it receives a <CR>. This will
signify the end of the transmission. The driver will then
generate a CRC based on the data and verify that it matches the
CRC sent. If it matches, an <ACK> will be sent. If not, a
<NACK> is sent, in which case the fields should be retransmitted
up to three times before aborting. A successful transmission
will signify that the next field(s) can be sent.

In the case of transmit, the driver will generate a CRC and send
it out at the end of the data string, followed by a <CR>. If it
receives an <ACK>, the next field can transmit. If it receives a
<NAK>, it will retry three times before aborting and reporting
back to the higher level application program.

The CRC calculated should include the command field and the data
field. The CRC should be sent as an ASCII string representing
the hexadecimal CRC code. For example, if the CRC calculated was
12BC HEX, then ASCII 1, 2, B and C characters should be sent for
the CRC.

LINK-20 USER'S MANUAL

LINK-20 COMMAND STRUCTURE

The Link-20 system is always under control of the computer. The
computer transmits a command to Link-20. The command way contain
data for the Spectrum or a request for data from the Spectrum.
Link-2Z always transmits a response back to the computer. The
response may ackncwled9e proper receipt of a command, signal an
error, or it may contain the requested data from the Spectrum.

In order to simplify the structure, all commands and responses
have the same general format.

<STX> (Function Code>b[Data]<ETX><CRC><CR>[<LF>]

The command and response are in ASCII.

The notational convention is as follows:

<STX> Start of text character 02HEX

<Function code> is a five digit number of the form:

DGGFF
D is a single digit reserved for destination
information. It should be the digit “4” in
Commands. Responses will return with the
diqit “3”.

GG is a two digit Command Group Code (see commands).

FF is a two digit field number, or the command
code extension of the specified command (see
commands).

b Space (blank) 20HEX

<Data> is an alpha-numeric string.
It must start with a printing character (not
space). It must contain only printing
characters or spaces. The data field may
not be present in all commands and responses.
Specific data field formats are required in
some commands.

<ETX> End of text character 03HEX
<CR> Carriage return character ODHEX
<LF> Line feed character OAHEX

The following sections will give commands and their normal
responses, error responses, and examples.

LINK-20 USER'S MANUAL

In addition to the error responses shown for specific commands,
there are several general error responses:

30002 ERROR Syntax error. The command is
not in a proper format.

30004 ERROR Undefined command.

30090 ERROR This command is not implemented.

NOTE: The complete error list is on Pg. 13.

GENERAL COMMAND GROUP (CODE 2)

40200 Request system identification.

NORMAL RESPONSE:

30200 <System ID>
Wbere <System ID is the Sales
Order Number of the Spectrum.

ERROR RESPONSE:

30006 ERROR
Command extension not defined.
EXAMPLE:

COMMAND 40200

RESPONSE 30200 SO-012800

LINK-20 USER'S MANUAL

CAS (Code Activated Switch)

A multidrop unit number must be selected for each Spectrum in the
system. A zero must be used for non-multidrop systems. The unit
number may be 1 through 15.

The Spectrum will be enabled by an arming code (ASCII DC3 or 13
Hex) followed by the unit number.

Be sure to select a unit number that is not used by any CAS
already in the system.

Note: The Spectrum will assert a RTS (request to send) before
each response, wait for the selected CTS (clear to send) delay,
then transmit it’s response. At the end of transmission, the
Spectrum will drop RTS.

LINK-20 USER'S MANUAL

OPEN. DELETE, CLOSE COMMAND GROUP (CODE 3) [TICKET]

40390 <Customer Code> Create and open a ticket.
When a ticket is open, the
Spectrum will display a
flashing '"c'" (communicating)
beside the ticket in Job
Index. The Spectrum system
can hold up to 200 tickets
in it’s job index, to be
batched upon command by
the Spectrum operator.
Open tickets cannot
be loaded or run until they
are closed. A ticket must be
open in order to perform any
of the following data transfer
operations.

NORMAL RESPONSE:

30390 <Ticket Code>

Where <Ticket Code> is a
decimal number (1-9,999,999)
which identifies this
particular ticket. It may be
used in subsequent commands to
access this ticket.

ERROR RESPONSES:
30007 ERROR

Attempt to create a ticket
when no space is available.

30010 ERROR

Attempt to create a ticket
while another ticket is open.

300ll ERROR

Attempt to create a ticket
while a customer file is open.

30012 ERROR

Attempt to create a ticket
while a product file is open.

LINK-20 USER'S MANUAL

40391 End ticket transfer
(close ticket)

NORMAL RESPONSE:

30391 <Ticket Code>

ERROR RESPONSE:

30009 ERROR

Attempt to close a ticket that
is not open.

40393 Delete an open ticket.

NORMAL RESPONSE

30393 <Ticket Code>

ERROR RESPONSE:

30015 ERROR

Attempt to delete while no
ticket is open.

LINK-20 USER'S MANUAL

Delete an existing ticket.

EXAMPLE:

COMMAND RESPONSE COMMENT

40500 2 Open Ticket Number 2
30500 00000
40393 Delete the Ticket
30393 00000

Note: The specific data items stored, their formats, and their
“field numbers” are defined by the "Ticket Record Definition",
Pgs. 19-21.

LINK-20 USER'S MANUAL

QUERY FIELD COMMAND GROUP (CODE 4) [TICKET]

404FF Query field number FF of
the current open ticket
(see 40390 or 40392).

NORMAL RESPONSE:

304FF <Data>

where <Data> is the
current field data.

ERROR RESPONSES:

30008 ERROR

Illegal field reference
(field number too large).

30009 ERROR

Attempt to query with no
ticket open.

EXAMPLE

COMMAND RESPONSE COMMENT

40392 2 Open ticket #2
30392 00002

40438 Query delivered quantity
30438 000030.00 30 yards delivered

40391 Close the ticket
30391 00002

Note: The specific data items stored, their formats, and their
"field numbers" are defined by the “Ticket Record Definition”,
Pgs 31-33.

Note: This feature not implemented.

LINK-20 USER'S MANUAL

FIND FIELD AMD OPEN COMMAND GROUP (CODE 5) [TICKET]

40500 <Data> Open the ticket
whose ticket number
matches
<Data>.

NORMAL RESPONSE

30800 <Ticket Code>

ERROR RESPONSES

30010 ERROR

Attempt to open a ticket
while another ticket is
open.

30014 ERROR

Attempt to open a
batching or loaded
ticket.

300l6 ERROR

Data field missing.

EXAMPLE

COMMAND RESPONSE COMMENT

40500 12345 Ticket number
30520 00002

LINK-20 USER'S MANUAL

TRANSFER BLOCK MODE COMMAND GROUP (CODE 6) [TICKET]

406FF <data> Transfer <Data> to
currently open ticket
using block mode
transmission. <Data> is
to start at field number
<FF> in the Ticket Record
(see Pg 32), and continue
through as many fields as
there is <Data> available
for. <Data> is of no
fixed length. Length of
zero is allowed. As many
fields as desired can be
sent in this manner, or
the record can be sent in
one large field. If
fields are sent
individually, this
command behaves exactly
as command <408FF>.

NORMAL RESPONSE:

306FF <Ticket Code>

ERROR RESPONSE:

30008 ERROR

Illegal field reference
(field * too large).

30009 ERROR

Attempt to transfer data
with no open ticket.

LINK-20 USER'S MANUAL

LINK-20 ERRORS

30001 Communication error
30002 Syntax error
30004 Undefined command
30006 Command extension not defined
30007 Attempt to create a ticket - no space
30008 Illegal field reference
30009 Attempt to transfer, close or query
an unopened ticket
30010 Attempt to create/open a ticket - another
ticket previously opened
30011 Attempt to create/open a ticket -
customer file presently open
30012 Attempt to create/open a ticket -
product file presently open
30013 Attempt to open a non-existing ticket
300l4 Attempt to open a batching or loaded ticket
30015 Attempted to delete ticket without opening
30016 Data field (ticket code) missing
30017 Attempt to access an unknown table
30018 Request command is incomplete - end of
buffer reached
30090 This feature has not been implemented

LINK-20 USER'S MANUAL

LINK-20 Function Code Summary

Ticket

Create
and Open 40390

Close 4039l

Delete 40393

Query
Field 404FF *

Open on
Ticket # 40500

Transfer
Block 406FF

* This feature has not been implemented.

LINK-20 USER'S MANUAL

LINK-20 TRANSFER BLOCK EXAMPLE 1

Good Transmission

Command Response

(1)

<STX>40390bBuilders<ETX><CRC><CR><LF>

(2)
<ACK> <STX>30390b00003<ETX><CRC><CR>

(3)
<ACK><STX>40600b23bbbbbBuildersbbJohnbSmithbCorp.bbbbbbbbbbbbbb
DublinbApartmentbComplexbbbbbbl234bFifthbAve.bbbbbbbbbbbbbbb
ColumbusbbbbbbbOh.
43212bbbbbbbbbb432lDeliverbtob3456bDublinbRd.bbbb<ETX><CRC><CR><LF>

(4)
<ACK><STX>30600b00003<ETX><CRC><CR>
(5)
<ACK><STX>40634b2500bbbbbbLowbSlumpbMixb#2bbbbbbbbbbbbbb
Ydsbbbbb8.00bbbb38.00bbbbb8.00bbbbb25.00bbbb200.00
<ETX><CRC><CR><LF>

(6)
<ACK><STX>30600b00003<ETX><CRC><CR>

(7)
<ACK><STX>40391b<ETX><CRC><CR><LF>

(8)
<ACK><STX>30391b00004<ETX><CRC><CR>

(1) Create and open a ticket.

(2) Ticket #3 opened

(3) Transfer block of data starting at Field 0.

Example:

Ticket # 23
Customer Code Builders
Customer Name John Smith Corp.
Customer Information Dublin Apartment Complex
Customer Address Line 1234 Fifth Ave.
City Columbus

LINK-20 USER'S MANUAL

(4) Block Received
(5) Transfer block of data starting at Field 38.

Example:

Product Code #1 2500
Description Low slump Mix #2
Unit of Measure Yds
Quantity this load 8.00
Total Ordered 38.00
Total Delivered 8.00
Price 25.00
Ext. Price 200.00

(6) Block Received
(7) Close Ticket
(8) Ticket Closed, next ticket is 00004.

LINK-20 USER'S MANUAL

LINK-20 TRANSFER BLOCK EXAMPLE 2

One transmission error and NAK

Command Response

(1)
<STX>40390bBuilders<ETX><CRC><CR><LF>

(2)
<ACK><STX>30390b00003<ETX><CRC><CR>

(3)
<ACK><STX>40600b23bbbbbBuildersbbJohnbSmithbCorp.bbbbbbbbbbbbbb
DublinbApartmentbComplexbbbbbbl234bFifthbAve.bbbbbbbbbbbbbbb
ColumbusbbbbbbbOh.
43212bbbbbbbbbb432lDeliverbtob3456bDublinbRd.bbbb<ETX><CRC><CR><LF>

(4)
<NAK>

(5)
<ACK><STX>40600b23bbbbbBuildersbbJohnbSmithbCorp.bbbbbbbbbbbbbb
DublinbApartmentbComplexbbbbbbl234bFifthbAve.bbbbbbbbbbbbbbb
ColumbusbbbbbbbOh.
43212bbbbbbbbbb432lDeliverbtob3456bDublinbRd.bbbb<ETX><CRC><CR><LF>

(6)
<ACK><STX>30600b00003<ETX><CRC><CR>

(7)
<ACK><STX>40634b2500bbbbbbLowbSlumpbMixb#2bbbbbbbbbbbbbb
Ydsbbbbb8.00bbbb38.00bbbbb8.00bbbbb25.00bbbb200.00
<ETX><CRC><CR><LF>

(8)
<ACK><STX>30600b00003<ETX><CRC><CR>

(9)
<ACK><STX>40391b<ETX><CRC><CR><LF>

(10)
<ACK><STX>30391b00004<ETX><CRC><CR>

(1) Create and open a ticket.

(2) Ticket #3 opened

LINK-20 USER'S MANUAL

(i) Transfer block of data starting at Field 0.

Example:

Ticket # 23
Customer Code 02
Customer Name John Smith Corp.
Customer Information Dublin Apartment Complex
Customer Address Line 1234 Fifth Ave.
City Columbus

(4) Noise on line causes data error and CRC test fails.
<NAK> is sent.

(5) Transfer block is repeated as in (3).

(6) Block Received

(7) Transfer block of data starting at Field 38.

Example

Product Code #1 25GB
Description Low Slump Mix #2
Unit of Measure Yds
Quantity this load 8.00
Total Ordered 38.00
Total Delivered 8.00
Price 25.00
Ext. Price 200.

(8) Block Received
(9) Close Ticket
(10) Ticket Closed, next ticket is 00004.

LINK-20 USER'S MANUAL

TICKET RECORD

Field # Description Length Type

0 Ticket # (Sequence #) 7 A
1 Customer Code 10 A
2 Customer Name 30 A
3 Customer Information 30 A
4 Customer Address Line 30 A
S City 15 A
6 State 3 A
7 Zip Code 10 A
S Account Number 10 A
9 Delivery Instruction Line #1 30 A
10 Delivery Instruction Line #2 30 A
11 Delivery Instruction Line #3 30 A
12 Delivery Instruction Line #4 30 A
13 De1Every Instruction Line #5 30 A
14 Delivery Instruction Line #6 30 A
15 Memo Line #1 19 A
16 Memo Line #2 19 A
17 Notes 30 A
18 Purchase Order # 10 A
19 Sales Order # 10 A
20 COD Flag (Y/N) 1 A
21 Credit Code 5 A
22 Order Tax Rate 9(xxxxx.xxx) N
23 Order Tax Code 4 A
24 Taxable 1 A
25 Project Code 9 A
26 Zone 9 A
27 Use 9 A
28 Reference # 3 N
29 Truck # 4 N
30 Driver Initials 5 A
31 Driver Name 15 A
32 Date (MM/DD/YY) 8 A
33 Time (HH:MM) 5 A
34 Spacing (Load Interval) (HH:MM) 5 A

LINK-20 USER'S MANUAL

TICKET RECORD
CONTINUED

35 Extra Product Code #1 (Concrete Product) 10 A
36 Description 30 A
37 Unit of Measure 3 A
38 Quantity This Load 9(xxxxxx.xx) N
39 Total Ordered 9(xxxxxx.xx) N
40 Total Delivered 9(xxxxxx.xx) N
41 Price This Product 10(xxxxxxx.xx) N
42 *Ext. Price This Load (Oty. * Price) l0(xxxxxxx.xx) N
43 Extra Product Code #2 10 A
44 Description 30 A
45 Unit of Measure 3 A
46 Type 1 A
47 Taxable 1 A
48 Quantity 9(xxxxxx.xx) N
49 Ordered 9(xxxxxx.xx) N
50 Delivered 9(xxxxxx.xx) N
51 Price l0(xxxxxxx.xx) N
52 *Ext. Price l0(xxxxxxx.xx) N
53 Extra Product Code #3 10 A
54 Description 30 A
55 Unit of Measure 3 A
56 Type 1 A
57 Taxable 1 A
58 Quantity 9(xxxxxx.xx) N
59 Ordered 9(xxxxxx.xx) N
60 Delivered 9(xxxxxx.xx) N
61 Price 10(xxxxxxx.xx) N
62 *Ext. Price 10(xxxxxxx.xx) N
63 Extra Product Code #4 10 A
64 Description 30 A
65 Unit of Measure 3 A
66 Type 1 A
67 Taxable 1 A
68 Quantity 9(xxxxxx.xx) N
69 Ordered 9(xxxxxx.xx) N
70 Delivered 9(xxxxxx.xx) N
71 Price l0(xxxxxxx.xx) N
72 *Ext. Price 10(xxxxxxx.xx) N

LINK-20 USER'S MANUAL

TICKET RECORD
CONTINUED

72 Extra Product Code #5 10 A
74 Description 30 A
75 Unit of Measure 3 A
76 Type 1 A
77 Taxable 1 A
78 Quantity 9(xxxxxx.xx) N
79 Ordered 9(xxxxxx.xx) N
80 Delivered 9(xxxxxx.xx) N
81 Price 10(xxxxxxx.xx) N
82 *Ext. Price 10(xxxxxxx.xx) N
83 Extra Product Code #6 10 A
84 Description 30 A
83 Unit of Measure 3 A
86 Type 1 A
87 Taxable 1 A
88 Quantity 9(xxxxxx.xx) N
89 Ordered 9(xxxxxx.xx) N
90 Delivered 9(xxxxxx.xx) N
91 Price l0(xxxxxxx.xx) N
92 *Ext. Price 10(xxxxxxx.xx) N
93 Previous Total l0(xxxxxxx.xx) N
94 *Ticket Total 10(xxxxxxx.xx) N
93 Sales Tax 10(xxxxxxx.xx) N
96 Ticket Total l0(xxxxxxx.xx) N
97 New Total 10(xxxxxxx.xx) N
98 slump 7(xxxx.xx) N
99 **Batch Flag (Y/N) 1 A
A0 Number of Loads 5 N
Al *Delivery Address Line One Extension 19 A
A2 Delivery Address Line Two Extension 19 A
A3 Other Address Line Extension 19 A
-- Spare 25 A

TOTAL LENGTH OF RECORD 1200

* NOTE: Spectrum does not re-compute or check
these prices or any amounts in any fields.

** NOTE: Y = Batch and print ticket
N = Don't batch, just print ticket

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