HSSI / Serial T3/E3 question

[mark.edwards]

I have a requirement to use T3/E3 speed interface cards. NM-1T3/E3 or NM-1HSSI would both appear to be appropriate. HSSI cards are cheaper, but I was wondering if there are any downsides to using HSSI ? Which would be the best choice ?

[mark-obrien]

You may need an external CSU/DSU-like device to convert the T3/E3 interface delivered by the carrier to the HSSI interface. Or, the carrier may deliver your service on a HSSI interface. Check with your carrier to find out what type of interface will be brought to your demarcation point.

Good Luck.

Mark

[mark.edwards]

Mark, sorry perhaps I was not clear with my question. From a design perspective, what are the differences between HSSI & T3/E3 cards. They are both valid options, but the HSSI cards are quite a bit cheaper. So, should I always use a HSSI card if possible ?

[t.baranski]

I believe the primary difference is that the HSSI requires an external CSU/DSU and the T3/E3 has one integrated. The T3/E3 may also have more advanced subrate functionality, but the exact differences aren't clear to me. You may want to talk to an account rep for more details.