Siemens Mux_guide_v06 - Manual (Page 28)

Multiplexer User's Guide
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Mux_guide_v06 Page 28 of 36 30.06.2004
4.3.9 Modem status command (MSC)
The Modem Status Command is used for software flow control.
Comman d
1 octet
Length
1 octet DLCI
1 octet V.24 signals
1 octet
Break Signals
(optional)
1 octet
Command:
Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8
1 C/R 0 0 0 1 1 1
Figure 11: Modem status command (MSC)
C/R bit: Indicates whether the sequence is a command or a response.
Length:
Length = 2 , EA-Bit = 1
DLCI:
Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8
1 1 DLCI
V.24 signals:
Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8
1 FC RTC RTR reserved 0 reserved 0 RING DCD
FC bit: Flow control, included in all multiplexer versions
FC = 1: no frames are accepted
The following bits for V24 status lines as described in this chapter are included in multiplexer
protocol version 3 only. However, if you wish to use the advantages of this version it is
absolutely necessary to switch on the version 3, otherwise version 1 will be used, see
Chapter 5.2.
Direction host application" module (for request only) MUX V3:
RTC: mapped to DTR
RTR: mapped to RTS
Bit 5, 6, 7, 8 are not valid.
Direction module " host application (for request only) MUX V3:
RTC: mapped to DSR
RTR: mapped to CTS
RING: mapped to RING
DCD: mapped to DCD
Bit 5, 6 are not valid