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5.5.
EXTENDED DATA SERVICES
Extended Data Services (XDS) information is encoded into Field 2 and is intended to supply program
related and other information to the viewer. XDS data can inform the viewer of such information as current
program title, length of show, type of show, time left in show, and V-Chip-compatible program rating
information.
The XDS output stream consists of a distinct XDS packet for each type of information. Each packet consists
of a 1 byte class, a 1 byte type, one or more informational characters, a 1 byte end of packet code, and a
1 byte checksum.
XDS packets are stored in the article memory and output in the XDS data channel in Field 2. These packets
are placed into the XDS output queue in the order specified by the user and inserted into Field 2 according
to the space available. CEA-608-B specifies that when there is caption or XDS information in field 2, then
there must be at least a null caption signal present in field 1 as well. When encoding into field 2, the MIO–
CCE–4K/3G automatically detects whether there is a caption signal present in field 1. If necessary, it will
turn on the Field 1 keyer automatically and turn it off again when upstream field 1 captions resume.
The computer uses an ASCII hex notation in describing the XDS packet id and data to the caption encoder.
For example, to specify the letter A enter a 4 followed by a 1 (the hex ASCII code for A is 41)
The XDS packets are deleted from memory when they have been transmitted the specified number of
times. XDS packets will be lost from the encoder's memory in the event of a power loss. The MIO–CCE–
4K/3G uses an advanced memory allocation scheme that allows it to store a virtually unlimited number of
XDS packets at one time. The only limit is the total amount of random access memory available.
Upstream XDS packets will be blocked in the output queue by packets of the same type.
5.5.1.
Input XDS
This command allows the user to input an XDS packet into the caption encoder's article memory.
If an XDS packet with identical edsid exists it will be deleted and replaced with the new packet definition.
Command:
^AP<sp>edsid<sp>rc<sp>data...data<cr>
Default:
none
The edsid parameter identifies the XDS packet id. The XDS packet can subsequently be referred to by its
packet id. If the XDS packet already exists, the new packet with the same id will replace the previous XDS
packet. The edsid is entered in ASCII hex notation. For example, to enter a packet id with a class of 01h
and a type of 23h, enter a 0 followed by a 1 followed by a 2 followed by a 3. The leading zero of the class
is optional.
The rc parameter identifies the number of times the packet will be repeated. Values of 9999 or FFFF
indicate that the packet should be repeated indefinitely. A packet's repeat count will be decremented each
time it is output.
The parameter data is the information bytes of the packet. This data is entered in ASCII Hex format. For
example, to enter the letter A enter a 4 followed by a 1 (the hex ASCII code for A is 41)
SMPTE ST 2110/4K/3G/HD/SD Closed Caption Encoder with Media–to–IP Streaming
Revision 1.0
MIO–CCE–4K/3G
Page - 65
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