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T1 Types?

ron.carney
Level 1
Level 1

I am trying to learn as much about T1s as possible. From what I have learned so far, I believe there are two types, a "regular" T1, and then a PRI, or Channelized T1. Is this correct?

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mohammedmahmoud
Level 11
Level 11

Hi,

We can say that generally there are 3 T1 types

unchannelized

channelized

PRI

In unchannelized operation, a T1 encapsulates the entire T1 payload (1536000 bits/second) .In channelized operation, a T1 port may be configured with up to N separate data streams (N = 24 for a T1 port). Each data stream may include any combination of time slots, either contiguous or not. Of course, each time slot may be included in only one data stream.

An ISDN PRI T1 implementation has 23 B channels and a D channel. As with BRI, each of the B channels has 64- kbps bandwidth available. The D channel, however, is also a 64-kbps channel (unlike BRI).

HTH, please do rate if it does help,

Mohammed Mahmoud.

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5 Replies 5

mohammedmahmoud
Level 11
Level 11

Hi,

We can say that generally there are 3 T1 types

unchannelized

channelized

PRI

In unchannelized operation, a T1 encapsulates the entire T1 payload (1536000 bits/second) .In channelized operation, a T1 port may be configured with up to N separate data streams (N = 24 for a T1 port). Each data stream may include any combination of time slots, either contiguous or not. Of course, each time slot may be included in only one data stream.

An ISDN PRI T1 implementation has 23 B channels and a D channel. As with BRI, each of the B channels has 64- kbps bandwidth available. The D channel, however, is also a 64-kbps channel (unlike BRI).

HTH, please do rate if it does help,

Mohammed Mahmoud.

That explains a lot, Mohammed, thank you so much. So, in a NON-ISDN, channelized T1, all 24 slots are the same, there is no B/D channels except in ISDN PRI? Is that correct?

Hi,

Sorry for the duplicated replies.

Yes you've got it right, in non ISDN the 24 slots are the same you can group them all in a non-channelized behavior, or you can group some of them together in a channelized behavior.

HTH, please rate if it does help,

Mohammed Mahmoud.

mohammedmahmoud
Level 11
Level 11

Hi,

We can say that generally there are 3 T1 types

unchannelized

channelized

PRI

In unchannelized operation, a T1 encapsulates the entire T1 payload (1536000 bits/second) .In channelized operation, a T1 port may be configured with up to N separate data streams (N = 24 for a T1 port). Each data stream may include any combination of time slots, either contiguous or not. Of course, each time slot may be included in only one data stream.

An ISDN PRI T1 implementation has 23 B channels and a D channel. As with BRI, each of the B channels has 64- kbps bandwidth available. The D channel, however, is also a 64-kbps channel (unlike BRI).

HTH, please do rate if it does help,

Mohammed Mahmoud.

Hi,

Sorry for the duplicated replies.

Yes you've got it right, in non ISDN the 24 slots are the same you can group them all in a non-channelized behavior, or you can group some of them together in a channelized behavior.

HTH, please rate if it does help,

Mohammed Mahmoud.

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