RFL Communications 21 Sub-MUX Manual de usuario descargar pdf (Pagina 6)

RFL SMX3 / 21 Page 6 of 22 Issue 1.4

User Manual

08 June 2009

6. X.21 Aggregate Port

The X.21 port is a DB15 male connector; this is connected internally to a header on

the PCB using a ribbon cable. The X.21 port may be configured as DTE or DCE by

fitting the ribbon cable to the appropriate X.21 Port Header, and by selecting settings

on DIP switch 5. Note: DTE is the standard configuration, and is used in all

applications where the network provides the signal timing.

Transceivers are specified to ± 15kV IEC1000-4-2 air discharge ESD protection and

port connections are additionally protected by Tranzorb type arrays.

This port carries an aggregate of three bi-directional data channels; one X.21

channel and two V.24 channels.

Standard X.21 Port Pin-out (when in DTE configuration) – D15M on chassis

Circuit Pin A Pin B Direction Notes

T Transmit Data 2 9 Output

R Receive Data 4 11 Input

C Control 3 10 Output Permanently on

I Indication 5 12 Input Signal ignored

Signal Element

Timing

6 13 Input Timing signal derived from

the network

G Ground 8 15

X Signal Element

Timing

7 14 Output Timing signal transmitted to

network (X). Special applications

only. Requires to be enabled

using mode DTE + Timing X

enabled

Screen / Drain

Must be earthed to shell

X.21 (DTE)

X.21 (DCE)

X.21 V24

X.21 header locations

Headers connected

to X.21 Port

Standard header location

DCE header location only

used when SMX3/40

provides signal timing

1 2 3 4 5 6 7 8 9 10 11 ... 21 22

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RFL Communications 21 Sub-MUX Manual de usuario Pagina 6