OPERATION
3.11.4 TO REQUEST OUTPUT OF TIME & STATUS MESSAGES
a. The computer (DTE) initiates the handshake by asserting DTR. The TM7000
responds by asserting DSR.
b. The computer then asserts RTS. The TM7000 responds by asserting CTS.
c. The computer outputs the first character of the command string.
d. After the character is received, the TM7000 removes CTS until the character has
been processed. When the TM7000 is ready for the next character, it will assert
CTS.
e. Steps “c” and “d” are repeated until a complete command has been transferred.
f. The TM7000 continues to assert CTS and outputs the required response (from one
to 15 characters).
g. After all time or status characters have been transferred, the computer may
remove both RTS and DTR until a new command is to be sent. Alternatively, the
computer may remove RTS, but continue to assert DTR in anticipation of a later
command transmission.
Note: If RTS is removed by the computer prior to completion of a time or status
output message, the TM7000 will finish the current character (if one is in
progress) and then pause until RTS is asserted again, at which time the output
message will be completed. If DTR is removed prior to completion of a time or
status output message, the TM7000 will finish the current character (if one is in
progress) and then abort the output process.
Note: Although inputs can be accepted by the TM7000 while it is outputting
data, a time or status command will not be processed while a time or status output
is in progress. As a general rule, it is best to consider this channel to be “half-
duplex” which means that traffic should be processed in only one direction at any
given time.
Symmetricom, Inc. TM7000 TymMachine TCG/T (Rev D) 3-29
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