Spectracom SecureSync 1200 User Reference Manual page 405

Model 1204-09 E1/T1 (75 Ω): Specifications
Outputs :
(1) 1.544/2.048 MHz Output
(2) Unbalanced E1/T1 Outputs
T1 mode :
1.544 MHz (square wave) frequency output
(2) 1.544 Mb/sec data rate outputs:
E1 mode :
2.048 MHz (square wave) frequency output
(2) 2.048 Mb/sec data rate outputs:
Connector and Signal Type : BNC
1.544/2.048 MHz TTL into 50 Ω
T1 according to GR-499-CORE (75 Ω)
E1 according to ITU-T G703 (75 Ω)
Maximum Number of Cards : 6
Ordering Information : 1204-09: T1/E1 (75 Ω) module
Figure 5-35:
Model 1204-09 option card rear plate
SecureSync User Reference Guide
Outputs are DS1 framed all ones
Supports Super Frame (SF or D4) and Extended Super Frame (ESF)
SSM support
Outputs are E1 frame all ones
Supports CRC4 and CAS Multiframe
SSM support
APPENDIX
389