Lucidata Diplomat jrNS User manual

Lucidata Diplomat jr
Model jrNS-CDF
Network Synchronous Server
Lucidata House
Selwyn Close
Great Shelford
CAMBRIDGE CB22 5HA
England
tel: [phone]
fax: [phone]
email: [email protected]

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
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Model jrNS-IB8
Publication Details All possible care has been taken in the preparation of this publication,
but Lucidata accepts no liability for any inaccuracies that may be found.
Lucidata reserves the right to make changes without notice to both this
publication and to the product which it describes.
If you find any errors in this publication or would like to make suggestions
for improvement, please write to the Company at the address below.
Lucidata House
Selwyn Close
Great Shelford
CAMBRIDGE
CB2 5HA
England
tel: [phone]
fax: [phone]
email: [email protected]
Diplomat ®is a registered trademark of Lucidata Limited.
© Lucidata Limited 2007
No part of this publication may be reproduced, transmitted, transcribed,
stored in any retrieval system or translated into any human or computer
language without the prior written permission of Lucidata Limited.
Diplomat jrNS-CDF User Guide Issue Number 1 (10/03)
Revision Details Issue First Published Revised Pages
1 10/03 11/03 9
02/04 8
06/05 2
08/07 1,2,3,9,10,11,20,21,22,23,28

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
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Table of Contents
Introduction Page 5
Getting Started Quickly Page 7
Port A Page 7
Port B Page 7
Power Page 7
Configuration Page 8
Pinouts and Links Page 8
Remote Configuration Page 9
JrConfig Program Page 9
JRemote Program Page 9
Local Diplomat jrNA Page 9
Factory Settings Page 10
Main Menu Page 10
Configuration Bytes Page 11
Network Parameter Page 15
Operation Page 18
Normal Network Operation Page 18
UDP Client/Server Page 18
TCP Client/Server Page 19
Opening TCP Sessions Page 19
Closing TCP Sessions Page 19
Normal Serial Port Operation Page 20
Data Flow Port A to Port B Page 20
Data Flow Port B to Port A Page 20
Special Cases Page 21
HDLC Data Stream Page 21
CRC16TerminatedDataStreamPage 21
Trouble Shooting
and Error Messages Page 21
LED Indicators Page 21
Basic Error Conditions Page 21
Statistics Display Port B Page 22
Network Trouble Shooting Page 23
Error Messages Page 25
Technical Specification Page 26
Synchronous Port A Page 26
Network Interface Port B Page 27
Product Details Page 28

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
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Warranty
All Lucidata products are designed, developed and tested under the
control of its ISO9000 compliant Quality Management System. The high
quality of our products is thus assured. Should any issues on the quality
of our products arise please address them to the Quality Manager at the
address given on page 2. This User Guide contains all the necessary
information for the proper installation and configuration of the product to
ensure the highest level of performance.
Warranty Lucidata warrants that the products described in this User Guide are
free from defects in manufacture and that they meet the specifications
and functionality described in this User Guide. Lucidata will replace parts
and repair defects in manufacture, on a return to factory basis, for a
period of 12 months from the date of our original invoice provided that
the product has only been used in the manner and for the purpose
described in this User Guide. Lucidata does not warrant that the products
described in this User Guide are suitable for any specific application
and the purchaser must satisfy him/herself of the suitability of the product
for the intended application as best known to him/herself. Lucidata does
not accept any contingent liability for any damages whatsoever including
direct, indirect, incidental, consequential, loss of business profits or
special damages arising from the use of its equipment. Lucidata assumes
that if its equipment is used in a business critical or any other essential
application, then the system design should incorporate sufficient
resilience to ensure that a single failure would not have disproportionate
consequences.
Service and Support If a unit fails, and you have bought it from a Lucidata appointed dealer,
you should contact that dealer. If bought from the manufacturer, return
the unit in its original packing to the address on page 2.
You should telephone or fax Lucidata prior to returning the unit to ascertain
whether an apparent fault is due to mis-operation rather than to a
technical fault within the unit and to obtain a returns number.
Lucidata reserves the right to charge for any investigation of an apparent
fault that is found to be due to incorrect operation, or for the repair of a
fault that is due to the unit not being used in accordance with the
instructions in this User Guide.
Maintenance Faults that occur outside the warranty period and are not covered by a
separate maintenance contract, will be repaired on a time-and-materials
basis. Please telephone Lucidata prior to returning your unit. You will be
given an estimate of the repair costs.

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
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Introduction
Introduction The Lucidata Diplomat model jrNS is one of a family of simple
connectivity solutions built around Lucidata’s popular Diplomat jr
product. The jrNS model has been designed specifically to interface to
the most common local area network (LAN) media utilising Ethernet
technology and employing the TCP/IP transport level protocols. Despite
network technology being rather complex, Lucidata has always sought
to make its products easy to use and user friendly. We believe that our
products should just be connected up and left to do their job with little
or no intervention necessary from the user.
To this end most Lucidata products are supplied with simple menu driven
configuration screens that can be accessed with any simple local terminal
or emulation. Remote configuration over the network is also possible
but due to the inherent security implications of such a method it is not
the default method.
The Diplomat jrNS is the member of the Diplomat jr family that enables
interconnectivity between an Ethernet/IP network and devices running
legacy frame synchronous protocols using serial RS232
communications. The protocol supported by a particular model is
determined by the firmware installed in the EPROM. The JRNS-CDF
supports the transport of a character delimited synchronous serial data
stream over a TCP/UDP/IP network using UTP Ethernet.
This manual is structured to require the minimum of reading to effectively
operate the Diplomat jrNS. If, as is our usual policy, Lucidata has
configured your unit for you, you will only need to read Chapter 2, Getting
Started Quickly, to discover what plugs into where and you will be on
the air.
If your unit is not configured yet you will need to read Chapter 3 on
Configuration to discover what information you need to get your hands
on before starting that process. If you are wondering why you bought a
Diplomat jrNS then Chapter 4, Operation, is where we tell of all the things
that the jrNS can do and how to drive it. You will probably want to read
this chapter anyway. Networks can be complex things and problems
can and do arise which may generate many and varied error messages,
some coming from within the Diplomat jrNS and others from outside
but reported to the interface. Chapter 5, Trouble Shooting and Error
Messages, documents these and gives probable explanations and
recommended courses of action. Finally Chapter 6, Technical
Specification, contains the dry detail of the hardware so you know what
pins to use.

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
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Synchronous Serial Port
RJ45 socket
10Base-T
BNC socket
10Base-2
Green LED Red LED
(Power)
Power
jack socket
8V DC
Yellow LED
Port B Port A
Getting Started Quickly
Network Interface
D25 Male

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
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Getting Started Quickly
When you hold the Diplomat jrNS in your hand so that the Diplomat jr
logo is oriented in the normal reading orientation, the Network end is to
the left and the Serial interface is to the right. For documentation purposes
we refer to the Serial interface as Port A and the selected network
interface as Port B.
Port A Port A is wired as a Serial Synchronous DTE and any cable that was
designed to connect a terminal type device to a modem using a 25 pin
female D type connector will be suitable to connect your DCE device to
Port A.
Port B Port B has a 10Base-T RJ45 connector and optionally a 10Base-2 BNC
connector. If both are present connection should be made to only one of
these connectors otherwise the Auto Media Sensing will get confused
and probably choose 10Base-2. The Auto Media Sensing only operates
at power-up time so changing the connector during operation will not
have the desired effect. The 10Base-T connector is wired for direct
connection to a hub using UTP cable.
Power The power lead from the mains adaptor is plugged into the socket on
the Port A end. When power is applied to the adaptor the Red LED by
the power connector should light. If it does not you probably have a dead
mains socket but refer to Chapter 5, Trouble Shooting and Error
Messages to discover what to do.
If you have selected the 10Base-T connector the Green LED by the
RJ45 socket should be illuminated to indicate a good link to the hub. If
not consult Chapter 5.
The Diplomat jrNS is now operational and should be doing what was
expected. If there is traffic on the network then the Yellow LED by the
RJ45 connector will be flashing.
If the Diplomat jrNS has been configured as a Server then it will just
wait until someone makes a connection over the network. If it is
configured as a Client then the Diplomat jrNS will attempt to make a
connection to the remote server defined in its configuration when the
configured initialisation condition occurs.

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Pinouts and Links Because the Synchronous Serial interface of the Diplomat jrNS has
been designed to be general purpose some of the 25 pins on the D25
male plug have a variable function. It is therefore essential that
connection is only made to those signals that are needed for a particular
application and to no others.
The following table lists all the pins and shows how they are assigned
for some standard applications. The default jumpers shown are for the
Diplomat jrNS to supply the clocks.
Pin No. Name Link L1 Link L3 Link L4 Link L5 Function
1 Screen Connected to groundplane
2 TXD jrNS Transmits Data
3 RXD jrNS Receives Data
4 RTS jrNS Signals Ready to Send
5 CTS External Cleared to Send
6 DSR N/C
7 Common Signal Return
8 DCD Q+R - - J+K Uses DCD Signal from DCE
P+Q - - - Held High Internally
15 TXC R+S - - K+L Uses External TX Clock from DCE
- B+C - - Uses External RX Clock from DCE
- A+B - - Uses Internal Clock
A+B - L+M Outputs Internal Clock on pin 15
17RXC----Uses External RX Clock from DCE
- - F+G - Outputs Internal Clock on pin 17
- C+D - - Uses Internal Clock iff IC20 removed.
20 DTR Held High by Diplomat
24 EXC Outputs Internal Clock always
Desired Interface IC2 IC20 Link L2
Serial Synchronous MC6852 MAX232 W+X,Y+Z
Serial Asynchronous MC6850 Remove X+Y
Configuration
NOTE: L1 MUST have either
P+Q or Q+R with J+K. This is
because DCD must not be left
floating

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
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Configuration
Remote Configuration All Diplomat jrNx can be configured remotely using one of two programs
or a local Diplomat jrNA. It is necessary in the case of the Diplomat jrNS
and Diplomat jrNP variants as they do not have an asynchronous RS232
port.
JrConfig Program The JrConfig program runs on a standard Windows PC and is self
documenting. It will assume it is on a Class C network and determine
the broadcast address for its subnet. When the Search Button is pressed
JrConfig will find all Diplomats present on the subnet. The selected
Diplomat is then available for configuring.
JRemote Program The JRemote program aims to give a similar presentation as would be
observed if a local connection had been made to a Diplomat fitted with
an asynchronous RS232 interface. It enables control as well as
configuration of the remote Diplomat. All that is required to initialise the
program is to fill in the IP address of the Diplomat it is desired to configure,
Tab to the Command text box and enter characters just as described in
the following section using a Diplomat jrNA. The displays invoked by the
Diplomat jrNA will appear in the large window of the program.
Local Diplomat jrNA The Diplomat jrNA should first be configured as a UDP Client with Error
Reporting using the following values for configuration bytes A and B.
A=11001100
B=10101010
In the Network Menu, the IP address of the remote jrN to be configured
should be substituted for the Remote IP address and the Server port
should be set to 12345. This is the reserved UDP port number that all
Diplomats use for configuration. Ensure that the Default Gateway is the
one required to obtain a route to the remote jrN. Send a few Pings to the
remote jrN using the "E" command to verify it is contactable. Then on
hitting the Return key three times a new Main Menu display should appear.
This Menu is coming from the remote jrN as is shown by the Terminal
Profile now showing "Remote Control" instead of "Local Port".
The following diagram shows the realationship between the various
clock and DCD selection links

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
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Factory Settings Should the configuration of the Diplomat jrNS become corrupted for any
reason so that it no longer responds to the IP address that was assigned
to it, it can be reset to the factory configuration. To do this make a D25
female socket with a link between pin 4(RTS) and pin 8(DCD) and plug
it into Port A. Power the unit up, wait 5 seconds, and power it down.
Remove the special socket and the unit will be reset to the factory defaults.
Main Menu
Lucidata Diplomat C 1995-2007
Model JRNS-CDF rev 1.02:5005
Terminal Profile is <Remote Control>
Type Single Digit to Select, <CR> to Exit
<A> Set Port A Configuration Byte
<B> Set Port B Configuration Byte
<C> Set Character Configuration Byte
<D> Set Data Rate Configuration Byte
<F> Set First Frame Byte
<L> Set Last Frame Byte
<I> Set Line Idle Byte
<S> Enter Statistics Menu
<N> Enter Network Control Menu
<R> Reset Diplomat Softly
Select < >
For all intents and purposes the Local Terminal is connected to the
remote Diplomat jrNS. All menu driving commands work in the usual
way with the exception that no control characters are sent to the remote
Diplomat jrNS. Make very sure of the changes that are made because
they will be remembered by the remote Diplomat jrNS when the Main
Menu is left and if the IP address has been changed erroneously you
may not be able to contact the Diplomat jrNS again without following
the reset procedure described earlier.
The remote Diplomat jrNS will also perform a soft restart after saving
the new configuration and any existing TCP connection will be lost.
It must be emphasized that typing Return when in the remote Main Menu
is necessary for new configuration values to be stored, but typing
CTRL/P at any time will return to the local Diplomat jrNA Main Menu if
one is being used. The remote Diplomat jrNS will be left in whatever
state it was in. Although the remote menu displays look the same as if
the configuration was being done locally they are actually performed in
parallel with whatever the remote Diplomat jrNS was doing at the time.
If no configuration values are changed because you only viewed the
statistics or got the remote Diplomat jrNS to Ping its Server then that
will not force a restart and any existing TCP session will be preserved.
Configuration

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Configuration Bytes The current generation of Diplomat jrs grew from a generation that had
lots of configuration switches on the PCB to set up options. This required
taking the lid off the box to make changes and in addition the switches
occupied valuable PCB space that could be better utilised for extra
functionality. The Diplomat jrNx has non-volatile memory so it can
remember any configuration details that it is given. For simplicity we
have introduced the concept of ‘Silicon Switches’ to select low level
options. They are directly analogous to ordinary switches but only exist
in the Diplomat’s memory.
In the Diplomat jrNS there are four sets of Silicon Switches associated
with four Configuration Bytes. Configuration Byte A controls the major
characteristics of Port A and Configuration Byte B controls the major
characteristics of Port B. Configuration Byte C allows specification of
the character format to be used on Port A and Configuration Byte D
determines the internal serial clock rate. There are also three application
level switches F,L and I for specifying framing characters.
Selecting A, B, C, D, F, L or I from the Main Menu will cause the appropriate
Configuration Byte to be displayed and the cursor will be positioned under
the first bit. At this stage the following characters can be typed in to
change the configuration byte:
CR - Return to Main Menu with the value of the configuration byte set to
the displayed value.
Space - move cursor to the right without changing the byte.
BS - move the cursor to the left without changing the byte.
0 - Change the ‘Switch’ above the cursor to 0 and move cursor right.
1 - Change the ‘Switch’ above the cursor to 1 and move cursor right.
Note - if any operation moves the cursor off either end the system returns
to the Main Menu.
Because the configuration bytes set low level properties of the Diplomat
they should be set up prior to attempting to configure the Network
parameters.
By convention the switches or bits of a configuration byte are numbered
as follows
76543210
Configuration

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Configuration Byte A Specifies Protocol on Port A
Bit Name Description
of Switch
2,0 BMBLK [111] - Mask to extract blocking size
[000] - Do not use blocking
[001] - Forward when 1 byte collected
[010] - Forward when 10 bytes collected
[011] - Forward when 50 bytes collected
[100] - Forward when 100 bytes collected
[101] - Forward when 200 bytes collected
[110] - Forward when 500 bytes collected
[111] - Forward when 1000 bytes collected
3 BCRTSF [0] - RTS is asserted when the unit has data to send
[1] - RTS is kept high while unit is powered up
4 BCDCD [0] - DCD is asserted when data is sent to the unit
[1] - DCD is kept high while the DCE is powered up.
5 BFFST [0] - Do not forward First Framing byte to the Network
[1] - Forward the First Framing byte to the Network
6 BFLST [0] - Do not forward Last Framing byte to the Network
[1] - Forward Last Framing byte to the Network
7 BFIDL [0] - Do not forward received idle bytes to the Network
[1] - Forward received idle bytes to the Network
Note (i) These bits determine the criteria for forwarding data from Port A onto the Network
Configuration Byte F defines the First Framing Byte
Configuration Byte L defines the Last Framing Byte
Configuration Byte I defines the Idle Byte.
Configuration

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
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Configuration Byte B defines Protocol on Port B
Bit Name Description
of Switch
0 BRSTAH [0] - Only allow current Host to Reset current TCP session
[1] - Allow any Host to Reset a current TCP session
1 BRSTAP [0] - Only allow current Port on current Host to Reset current
TCP session
[1] - Allow any Port on current Host to Reset current session
2 BPEER [0] - Only allow Client/Server relationships
[1] - Allow Client/Client relationships
3 BSTART [0] - Wait for Port data before starting TCP session
[1] - Start TCP as soon as powered up
4 BSERVR [0] - Behave as a Client device
[1] - Behave as a Server device
5 BDCDF [0] - Ignore DCD dropping on Port A
[1] - Close any open TCP session if DCD drops
6 BTCPUD [0] - Use TCP protocol
[1] - Use UDP protocol
7 BEXREP [0] - Do not report network originated errors
[1] - Report ICMP network messages in text form to Port A
Note (i) If BPEER=1 the unit will allow a remote host to establish a TCP session with it if, and only if, the IP
address and the Port address of the remote host are the same as those declared in the Network
Menu for Remote IP Address and Remote TCP Server Port.
Note (ii) BEXREP must be set to zero in model DCF
Configuration

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
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The meaning of the bits in Configuration Byte C are given in the following
table.
Data Parity Bit 5 Bit 4 Bit 3
Bits Bits
6E000
6O001
7N010
8N011
7E100
7O101
8E110
8O111
Where the Parity Bit Codes mean None, Even or Odd
The meaning of the bits in Configuration Byte D are given in the following
tables.
Clock 1 (T1) is controlled by bits 0 to 3
Speed Bit 3 Bit 2 Bit 1 Bit 0
(bps)
75 0000
150 0 0 0 1
300 0 0 1 0
600 0 0 1 1
1200 0 1 0 0
2400 0 1 0 1
4800 0 1 1 0
9600 0 1 1 1
19200 1 0 0 0
38400 1 0 0 1
14400 1 0 1 0
28800 1 0 1 1
38400 1 1 0 0
38400 1 1 0 0
38400 1 1 0 1
38400 1 1 1 0
38400 1 1 1 1
Configuration
Note Clock 1 only controls the Transmit Clock (TXC) in model CDF

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
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Now that the basic configuration of the Diplomat jrNS has been performed
we can safely move on to setting up the Network Parameters.
Typing ‘N’ at the Main Menu will bring up the Network Control Menu.
Network Control Menu -
Diplomat is configured as a TCP Server
Our Ethernet Address is - 00 A0 EF 00 00 0C
Our Diplomat IP Address is - 128.18.18.12
Default Remote IP Address - 128.18.18.255
Default Gateway IP Address - 128.18.18.255
Default Sub-Net Address Mask - FFFFFF00
Default TCP/UDP Service Port Id. - 7000
Status of TCP Session - CLOSED
<O> Set Our IP Address
<S> Set Remote/Server IP Address
<G> Set Gateway IP Address
<M> Set Sub-Address Mask
<P> Set Server Port Id.
<C> Set Client Port Id.
<F> Firewall Definition Menu
<A> Broadcast ARP Request
<B> Broadcast BOOTP Request
<R> Broadcast RARP Request
<E> Send ECHO Request to Remote
<CR> Returns to Previous Menu
Network Parameter
Configuration
Configuration
GATEWAY
Diplomat jr
CLIENT
Local Ethernet
Remote Ethernet
OUR IP ADDRESS
GATEWAY IPADDRESS
LOCAL HOST
SERVER IP ADDRESS
(LOCAL)
REMOTE HOST
SERVER IP ADDRESS
(REMOTE)

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
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In the above screen the Diplomat has been configured as a Server. In a
later screen the slight differences when it is configured as a Client will
be obvious.
The Ethernet Address is unique to the unit and cannot be changed. It is
displayed for information only.
The three IP Addresses are all changed in the same way. First a key
letter is selected:
'O' to set the Local IP Address of the Diplomat itself, 'S' for the Remote
host and 'G' for the local Gateway. If there is no local gateway then the
gateway address should be set to the same as the remote host. The
following is a typical prompt:
Enter New IP address in Decimal Dot Notation
Address of this Diplomat (Client/Server) -
If the Return key is entered no changes are made and the screen
refreshes to show the current values. Fields may be skipped by typing a
‘.’ until the field you want to change is reached and then simply typing
the new decimal value and hitting Return will update the value.
At this point, contact will be lost with the remote Diplomat jrNS. The
Host jrN should now be re-configured so that it uses the new Remote IP
address to re-establish contact with the remote jrNS.
Whether you are using Sub-Networking on your network or not the Sub-
Net mask should be such that when applied (perform a bitwise AND
operation) to both the Local IP Address and the Remote IP Address the
masked values match. If a local gateway is used then the masked
Gateway IP Address should match the masked Local IP Address. ie
communicating devices must be on the same conceptual sub-net.
Typing ‘M’ will invoke the following response:
Enter Sub-Address Mask in hex
You should now enter the full eight hex characters to specify the 32 bit
mask.
The TCP/UDP Local Service Port is the port number that a Client host
will use to make a connection to the Diplomat when it is acting as a
Server. The Diplomat will not respond to attempts to communicate with
any other port number.
Typing ‘C’ will invoke the following response:
Enter TCP Port Address in Decimal -
Care should be taken to ensure that the value chosen is within the range
allowed by the remote host TCP/IP stack. Some systems impose
restricted ranges ie.2000 to 4000.
Configuration

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
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When the Diplomat is configured as a Client there are two port addresses
required. This time the Service Port is the Server Port number that the
Diplomat will try to establish a connection with on the Server and the
Client Port number is the Diplomat’s own local port ID.
If the value of 23 is chosen for the Service Port the Diplomat will perform
Telnet control character processing by adding or removing NUL
characters after CR characters.
The Port value 12345 should not be used as it is reserved for remote
interrogation of the Diplomat jrNS.
Typing ‘F’ will invoke the Firewall Definition Menu
Firewall Definition Menu - feature activated by non-zero
values
Acceptable Hosts and Ports
1. 0.0.0.0 : 0
2. 0.0.0.0 : 0
3. 0.0.0.0 : 0
4. 0.0.0.0 : 0
5. 0.0.0.0 : 0
6. 0.0.0.0 : 0
7. 0.0.0.0 : 0
8. 0.0.0.0 : 0
<C> Clear All entries, Disable feature
<A> Add an entry, <D> Delete an entry, <E> Edit an entry
<CR> Returns to Previous Menu
The feature only has effect if the Diplomat jrNS has been configured
as a Server or Peer. The Firewall is activated by defining a non-zero IP
address. When activated the remote host IP address defined in the
Network Control Menu is ignored and only those hosts defined in the
firewall list will be able to start up a TCP session or enter into a UDP
exchange. IP and port values are entered in exactly the same manner
as described for the previous menu.
The Status of the TCP session is shown for information purposes and
will be unaffected provided that no changes are made to the network
parameters. Therefore it is possible, during an active session, to
interrogate the Network Control Screen without causing any damage to
the active session.
Configuration

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
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Operation
Normal Network As long as the Diplomat jrNS is properly configured and is not in Network
Monitor mode it is in the Normal Mode of operation. It will process the
following Ethernet message types:
ARP messages addressed to the local IP address
RARP messages containing the local Ethernet address
ICMP messages addressed to the local IP address
UDP messages addressed to the local IP address and the local port or
the configuration port
UDP messages addressed to the Broadcast IP address and the local port
or the configuration port
TCP messages addressed to the local IP address and the local port
Responses to ARP, RARP and ICMP are performed automatically and
the user will in general be unaware of the activity. ARPs have no effect
other than providing or giving essential information about Ethernet and
IP addresses but a RARP request can cause the Diplomat jrNS to change
its IP address to the value contained in the RARP reply.
When the Diplomat jrNS is configured as a Client it checks to see if it
has a good Ethernet address for either the Default Gateway or Remote
Server and issues an ARP if it does not. If the Diplomat jrNS determines
that the Remote Server Address is on a different Sub-Network to itself it
will address the ARP to the Default Gateway. The Ethernet address
contained in the ARP reply will be used subsequently to address packets
to the Remote Server. This process is repeated every 2 seconds until a
valid reply has been received.
The Diplomat jrNS cannot send data until it has a valid ARP entry in its
tables. For this reason an entry is preset into the ARP table for the Sub-
Network broadcast IP address (host address of all ones) together with
an Ethernet address of all ones. This is to enable a UDP client to generate
UDP broadcasts if the Remote Server IP Address is set equal to the
Sub-Network broadcast IP address. In this case the Diplomat jrNS does
not issue any automatic ARP requests.
The Diplomat jrNS may be set up as a UDP Client or Server, or a TCP
Client or Server. The following paragraphs describe the properties of
each set up.
UDP Client/Server When configured as a UDP Server the Diplomat jrNS will wait until a
UDP packet is received from a remote host which is addressed to the
local IP address and Server Port held in the jrN. The Diplomat jrNS
cannot send any data over the network until it has received a packet
containing a Source Port and IP address for it to use as a return address.
If a UDP packet arrives from another host before the Diplomat jrNS has
sent a reply to the previous host, the new packet will be ignored unless
switch BRSTAH = 1. If BRSTAH = 1 the new packet's Source IP and
Port addresses become the new Destination addresses for any Diplomat
jrNS reply.
Operation

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
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Operation
When the Diplomat jrNS is configured as a UDP Client it will transmit a
UDP packet over the network as soon as it has some qualified data to
send. It will use the Remote Host address and Server Port address held
in its tables to address the packet and will use its own Client Port address
for the Source Port address field in the transmitted packet.
If switch BPEER=1 then the Diplomat jrNS will accept an initial contact
as if it were configured as a Server, provided that the packet came from
the Remote IP address and Server Port held in its tables.
The UDP service is a connectionless service with no guarantee of delivery.
Only data contained in UDP packets whose header checksums are
correct are passed on transparently to Port A.
TCP Client/Server When configured as a TCP Server the Diplomat jrNS will wait until a
remote host attempts to establish a TCP Session with it. This requires
a proper three way handshake and matching Destination IP and Port
Addresses to those held within the jrN. The Source Port address and IP
address of the remote host are stored locally for use as a return address.
Should a new attempt to initiate a TCP session be detected from the
same IP address and port, then the existing session is considered broken
and the Diplomat jrNS returns to its initial waiting state after first issuing
a Reset to the old session. Similarly if the remote host sends a Reset or
Close command then the Diplomat jrNS terminates the current session
and returns to the waiting state.
These rules are relaxed if switch BRSTAH = 1. If BRSTAH = 1 any new
host attempting to initiate a TCP session will cause the current session
to issue a Reset to the old session and close down. The second attempt
by the new host will be successful. In addition if BRSTAP = 1 any Reset
packet received will be actioned if it comes from the current host IP
address but need not be from the same port.
Neither switch has any effect if the Firewall feature is enabled as this
alone will determine who is able to talk to the Diplomat jrNS. New session
requests or Reset commands from any Firewall qualified host/ports will
be accepted and actioned as described above. The Diplomat jrNS cannot
initiate a TCP session when in Server mode.
Opening TCP Sessions When configured as a TCP Client the Diplomat jrNS will attempt to initiate
a TCP session with the Remote Server on the declared Server Port as
soon as it has qualified data to send. Only packets from the Remote
Server IP address and Port address will be processed.
Closing TCP Sessions In both modes the user has control over the closing of active TCP
sessions.

Diplomat jr Model jrNS-CDF User Guide Issue No. 1 (08/07)
20
Operation
The model CDF uses Character Delimited Framing to handle the data
flow on the synchronous port. In its idle mode - that is when there is no
data available from the network - the synchronous port asserts pin 4
(RTS) OFF if bit BCRTS=0 or permanently ON if BCRTS=1. The internal
clock is always available on pin 24 and as a Transmit Clock (TXC) on
pin 15. If BCRTS=0 the idle Transmit Data (TXD), pin 2, is held in the
MARKING state but if BCRTS=1 the transmitter keeps sending the Idle
character defined by Configuration Byte I. An idle condition from the
connected DCE is sensed when pin 8 (DCD) is OFF and the Received
Data (RXD), pin 3, is MARKING. If bit BCDCD=1 then the DCE may be
transmitting idle characters but unless the Diplomat's receiver has been
previously synchronized they will not be seen.
Data flow Port A to Port B The Receiver remains unsynchronized until a character which matches
the FIRST character defined by Configuration Byte F appears on the
line. If bit BFFST=1 it is copied to the network buffer otherwise it is
discarded. Consecutive bytes are copied to the network buffer until a
character matching the LAST character defined by Configuration Byte L
is encountered. If bit BFLST=1 this character is copied to the network
buffer and the network application notified there is a packet to send over
the network. If the field defined by BMBLK is non-zero then the byte
count determined by that field will control when a packet is sent over the
network. The network buffer will always be flushed to the network when
DCD drops or the maximum TCP segment size (1460) has been
accumulated. The tests controlling forwarding are always performed in
the following order.
i) Has DCD dropped?
ii) Has the maximum TCP segment size been reached?
iii) Is a forwarding block size defined and has it been reached?
iv) Have we been notified of a completed packet?
If BCDCD=1 the Diplomat will continue to receive idle characters and if
bit BFIDL=1 they will be forwarded to the network buffer. If BCDCD=0 or
BFIDL=0 the synchronization of the receiver is cleared so that no more
data is forwarded until the occurrence of another FIRST character.
Data flow Port B to Port A When data arrives from the network the complete packet is copied to
the port buffer. If the Transmitter is already transmitting the data is just
appended to the current stream. If the Transmitter is idle the first character
of the new data is compared to the FIRST character. If it matches FIRST
it and all following characters are transmitted over the line. If the first
character does not match FIRST and bit BFFST=0 a FIRST character
is output ahead of the new data stream. When the data stream from the
network runs out the last character is examined and if it does not match
LAST and bit BFLST=0 then a LAST character is sent out as a final
character.
Byte data is shifted in and out on the synchronous lines Least Significant
Bit (LSB) first.
Normal Serial Port
Operation