Rev 0.11
Page G.703-1
Appendix G5 G.703/E1 Interface
PSM-500 Series G.703/E1 Interface Addendum
Revision History
Rev 0.10
2-1-2012
Initial Release.
Rev 0.11
5-2-2012
Corrected E1 transport stream descriptions. Corrected front
panel menu entries.
1.0
Optional G.703/E1 Interface Overview
G.703/E1 is a legacy interface standard that is used in Telephony and Cellular Backhaul
applications. The installation of the optional G5 (G.703/E1) interface provides the M500 Class
modems (PSM-500/500L/500LT) with an economical access solution for E1 and Fractional E1
network services over satellite. The G5 fully meet all of the E1 rate 2048 kbit/s specifications
including ITU recommendations:
G.703 - Physical/electrical characteristics of hierarchical digital interfaces.
G.704 - Synchronous frame structures used at 1544, 6312, 2048, 8448 and 44 736
kbit/s hierarchical levels.
G.706 - Frame alignment and cyclic redundancy check (CRC) procedures relating to
basic frame structures defined in Recommendation G.704.
G.732- Characteristics of primary PCM multiplex equipment operating at 2048 kbit/s.
G.823 - The control of jitter and wander within digital networks which are based on the
2048 kbit/s hierarchy.
NOTE: If the G5 interface card is not already installed in the modem refer to Section 4 for
installation information.
Typical use of the G5 interface is in a duplex point to point link with a similarly configured PSM-
500 series modem at the other end of the link. The setup of the satellite link is very simple
because the modems at both ends of the link are connected to DTE equipment with this same
G.703/E1 interface type. Each port of the G5 interface can be configured independently for
either Full E1 or Fractional E1 operation.
The Full E1 mode allows for transmission of an the 2.048Mbps input data stream without
synchronizing to the imbedded framing of the E1 signal. In this case the port data rate though the
satellite link is the full 2.048Mbps of the E1 transport stream. Note in Unframed E1 there is no
requirement for G.704 framing.
The Fractional E1 mode allows for data rates of Nx64kbps to be transmitted over the satellite.
The G5 interface has flexible selection the number of timeslots to be transmitted and for selection
of standard signaling formats.
PCM30-CAS (Channel Associated Signaling) (Nx64Kbps, N = 1 to 15, 17 to 31 TS).
PCM31-CCS (Common Channel Signaling) (Nx64Kbps, N = 1 to 31 TS).
The FullE1 or Fractional E1 modes are controlled via the G.703 Frame parameter. Any
combination of Full E1 or Fractional E1 can be used independently on each port, and can be
used independently on the transmit or receive side of each port.
