Appendix A: Data Interface Information; General - Paradise Datacom P300 Series Installation & Operating Handbook

APPENDIX A: DATA INTERFACE INFORMATION

GENERAL

Unlike previous Paradise Datacom products, the standard interface of the P300 Series Modem DOES NOT
SIMPLY UNPLUG. Instead to reduce the cost of the modem the interface is built as a standard part of the
main PCB and includes RS422, V.35, and RS232 modes. An additional G.703 interface may be fitted
internally to provide front panel selection between RS422, V.35, RS232 and G.703.
IT IS POSSIBLE TO FIT OTHER INTERFACES, and in fact the whole Paradise P14xx range can be utilised
in the P300 series modem. However, prior to fitting another interface the case must be opened, the
standard interface `snapped off` from the main PCB, and a 48 pin connector fitted to the main PCB to
accept the plug in cards. It is advisable to return the equipment to the factory for this to be done, although
it is perfectly possible in the field.
1:1 OPERATION
The standard RS422, V.35, and RS232 interface does not require any resistor packs to be unplugged for
1:1 redundancy operation. HOWEVER the G.703 option has a switch to set the mode (Normal or 1:1) and
the E1 G.703 card a second switch to select 120 / 75 operation. The Normal/1:1 switch on the G.703
S S
option doubles the impedance (so you can connect the two in parallel) and also selects what happens when
power is removed. If the power is lost in "Normal" mode the G.703 input and output are joined so that if in
Drop/Insert operation the G.703 signal is looped through multiple equipments, the other traffic is not
affected by a break in the G.703 line. If the power is lost in "1:1" mode the G.703 output goes high
impedance if power is lost, allowing its 1:1 partner to carry the traffic.
Unlike previous interfaces, the standard P300 Series interface does not provide a pin on the connector
which can make the interface go high impedance.
HANDSHAKE LINES
Many interfaces provide optional control lines (such as RTS/CTS etc). It is generally better to implement
these between equipments if possible.
P300H P300 Series Modem Installation and Operating Handbook Page 167