Perle Systems IOLINK-520 - Manual (Page 95)

IOLINK-520 & IOLINK-PRO Installation & Applications Guide — D. 1
Appendix D
Interface Pinouts
Pinout Information
Each link interface available is described with detailed information on pin designation. Standard
interface cables will provide correct connections to modems, datasets, or DSU/CSUs.
When connecting two bridge/routers back-to-back without modems, a null-modem cable is
required to crossover the pins on the links. Crossing over the pins allows two
bridge/routers both configured as DTE interfaces to be connected together. With this
configuration, both bridge/routers will provide clocking for the links, and each
bridge/router must have a link speed defined.
Link Clocking Information
All of the link interfaces on the IOLINK router act as DTE devices, this means that they
may be directly connected to DCE devices (modems, etc.) with the DCE devices providing
the clocking for the link. The link speed is controlled by the DCE device. Setting the link
speed on the IOLINK router will not result in a speed change on the link.
Some DCE devices allow the DTE devices connected to them to supply a clock signal
which is then routed back to the transmit clock pins on the DCE interface. This clock is
then received by the IOLINK router link interface. By using this method, the IOLINK
router may be in control of the link speed. The link speed may also be controlled by the
IOLINK router when a null-modem cable is used to connect two IOLINK routers in a
back-to-back configuration.
Changing the link speed within the menu system of the IOLINK router changes the clock
output speed that is generated on the DTE Terminal Timing pins (external clocking pins) on
the link interfaces.
ATL-CSU/DSU Link Module Information
The IOLINK-520 & IOLINK-PRO are currently produced with LXT CSU/DSU interface
modules; however, the earlier model ATL CSU/DSU module is still compatible with the
IOLINK router and may be used with it. Note that ATL master mode signaling is not
compatible with the current standard 64K master mode signaling; therefore, for back to
back connections, an ATL unit will only operate at 64K when connected to another ATL
unit. If one interface is an ATL unit and the other is not, back to back operation must be set
to 56K.
The ATL-CSU/DSU link module is normally configured to receive clock from the
connected network. When two ATL-CSU/DSU link modules are to be used on a leased
line in a back-to-back set-up, one of the modules must provide the clock.