FiberPlex TD-1580 - Manual (Page 12)

Other Considerations
Application Flexibility
The units support tail circuit and null modem functions for DCE to DCE or DTE to DTE communications. This
requires two of the same TD unit.
An alternate interface (V.35 or RS‐232) may be installed at the opposite end, allowing the user to create a link
between two electrically incompatible interfaces without requiring a separate interface converter. For more
information, please see the “Optical Compatibility” table.
SFP MSA Compliance
The SFP Multi Source Agreement (MSA) is an agreement that was drafted among competing manufacturers of
SFP optical modules. The SFF Committee was formed to oversee the creation and maintenance of these
agreements including the SFP MSA designated as INF‐8074i. This agreement describes a mutually agreed upon
standard for the form and function of SFP modules. However, not all SFPs produced are MSA compliant. The
MSA provides for a transceiver (TX/RX) pinout. Other industries such as broadcast had the need for dual TX
and dual RX SFP for uni‐directional applications such as video. Naturally, a non‐MSA standard was introduced
allocating pinout assignments for dual output and dual input I/O configurations. In addition, the some of the
internal serial communication pins were reassigned.
The TD‐1580/TD‐1581 will only accept MSA compliant SFP modules which support the specified data rate.
Pinout Comparison Chart
PIN Transceiver (MSA) Transceiver (Non‐MSA) Dual TX (Non‐MSA) Dual RX (Non‐MSA)
1 VEE VEE VEE VEE
2 TX_FAULT [VEE] VEE NC Rx2‐
3 TX_DIS NC NC Rx2+
4 MOD_DEF(2) ‐ SDA VEE VEE VEE
5 MOD_DEF(1) ‐ SCL SCL SCL SCL
6 MOD_DEF(0) – PRESENCE [VEE] SDA SDA SDA
7 Rate [NC] VEE VEE VEE
8 LOS RX1_LOS Tx2+ NC
9 VEE NC Tx2‐ NC
10 VEE NC Tx2_DIS NC
11 VEE VEE VEE VEE
12 RD‐ Rx1‐ NC Rx1‐
13 RD+ Rx1+ NC Rx1+
14 VEE VEE VEE VEE
15 VCC VCC VCC VCC
16 VCC VCC VCC VCC
17 VEE VEE VEE VEE
18 TD+ Tx1+ Tx1+ NC
19 TD‐ Tx1‐ Tx1‐ NC
20 VEE Tx1_DIS Tx1_DIS NC